Quarterly report pursuant to Section 13 or 15(d)

Revenue from Contracts with Customers - Impact on Statement of Financial Condition (Details)

Revenue from Contracts with Customers - Impact on Statement of Financial Condition (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017	Sep. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cash and cash equivalents	$ 262,834	$ 172,103	$ 172,103	$ 100,739
Securities owned, at fair value	5,451	3,881	3,881
Receivables from clearing brokers	26,650	48,543	48,543
Receivables from other broker-dealers	1,472	2,822	2,822
Notes receivable from financial advisors, net	6,520	6,803	47,369
Other receivables, net	130,507	119,356	60,707
Fixed assets, net	28,590	23,621	23,621
Restricted cash	6,589	760	760
Intangible assets, net	74,233	79,966	103,611
Goodwill	125,966	124,210	124,210
Contract acquisition costs, net	77,803	61,340	0
Cash surrender value of life insurance	13,478	12,711	12,711
Other assets	40,498	31,712	31,687
Total assets	800,591	687,828	632,025	$ 552,615
Securities sold, but not yet purchased, at fair value	66	231	231
Accrued compensation	32,013	33,233	33,343
Commissions and fees payable	109,247	96,616	67,221
Accounts payable and accrued liabilities	50,122	39,241	40,478
Deferred rent	2,970	2,151	2,151
Deferred income taxes	12,659	6,603	2,968
Deferred compensation liability	21,963	18,161	18,161
Accrued interest	0	232	232
Notes payable	185,199	96,849	96,849
Total liabilities	414,239	293,317	261,634
Commitments and contingencies (Note 11)
Preferred stock	2	2	2
Common stock	20	20	20
Additional paid-in capital	487,752	520,135	520,135
Accumulated deficit	(101,467)	(125,669)	(149,778)
Total shareholders’ equity of the Company	386,307	394,488	370,379
Noncontrolling interest	45	23	12
Total shareholders' equity	386,352	394,511	370,391
Total liabilities and shareholders' equity	800,591	687,828	632,025
Calculated under Revenue Guidance in Effect before Topic 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cash and cash equivalents	262,834		172,103
Securities owned, at fair value	5,451		3,881
Receivables from clearing brokers	26,650		48,543
Receivables from other broker-dealers	1,472		2,822
Notes receivable from financial advisors, net	57,983		47,369
Other receivables, net	69,161		60,707
Fixed assets, net	28,590		23,621
Restricted cash	6,589		760
Intangible assets, net	93,937		103,611
Goodwill	125,966		124,210
Contract acquisition costs, net	0		0
Cash surrender value of life insurance	13,478		12,711
Other assets	39,976		31,687
Total assets	732,087		632,025
Securities sold, but not yet purchased, at fair value	66		231
Accrued compensation	32,115		33,343
Commissions and fees payable	78,635		67,221
Accounts payable and accrued liabilities	50,536		40,478
Deferred rent	2,970		2,151
Deferred income taxes	6,549		2,968
Deferred compensation liability	21,963		18,161
Accrued interest	0		232
Notes payable	185,199		96,849
Total liabilities	378,033		261,634
Commitments and contingencies (Note 11)
Preferred stock	2		2
Common stock	20		20
Additional paid-in capital	487,752		520,135
Accumulated deficit	(133,754)		(149,778)
Total shareholders’ equity of the Company	354,020		370,379
Noncontrolling interest	34		12
Total shareholders' equity	354,054		370,391
Total liabilities and shareholders' equity	732,087		632,025
Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract acquisition costs, net		40,566
Accounting Standards Update 2014-09 \| Difference between Revenue Guidance in Effect before and after Topic 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cash and cash equivalents	0
Securities owned, at fair value	0
Receivables from clearing brokers	0
Receivables from other broker-dealers	0
Notes receivable from financial advisors, net	(51,463)
Other receivables, net	61,346
Fixed assets, net	0
Restricted cash	0
Intangible assets, net	(19,704)
Goodwill	0
Contract acquisition costs, net	77,803
Cash surrender value of life insurance	0
Other assets	522
Total assets	68,504
Securities sold, but not yet purchased, at fair value	0
Accrued compensation	(102)
Commissions and fees payable	30,612
Accounts payable and accrued liabilities	(414)
Deferred rent	0
Deferred income taxes	6,110
Deferred compensation liability	0
Accrued interest	0
Notes payable	0
Total liabilities	36,206
Preferred stock	0
Common stock	0
Additional paid-in capital	0
Accumulated deficit	32,287	$ 24,109
Total shareholders’ equity of the Company	32,287
Noncontrolling interest	11
Total shareholders' equity	32,298
Total liabilities and shareholders' equity	$ 68,504
Accounting Standards Update 2014-09 \| Difference between Revenue Guidance in Effect before and after Topic 606 \| Investment Banking
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cash and cash equivalents			0
Securities owned, at fair value			0
Receivables from clearing brokers			0
Receivables from other broker-dealers			0
Notes receivable from financial advisors, net			0
Other receivables, net			(137)
Fixed assets, net			0
Restricted cash			0
Intangible assets, net			0
Goodwill			0
Contract acquisition costs, net			0
Cash surrender value of life insurance			0
Other assets			25
Total assets			(112)
Securities sold, but not yet purchased, at fair value			0
Accrued compensation			(110)
Commissions and fees payable			0
Accounts payable and accrued liabilities			(104)
Deferred rent			0
Deferred income taxes			28
Deferred compensation liability			0
Accrued interest			0
Notes payable			0
Total liabilities			(186)
Commitments and contingencies (Note 11)
Preferred stock			0
Common stock			0
Additional paid-in capital			0
Accumulated deficit			74
Total shareholders’ equity of the Company			74
Noncontrolling interest			0
Total shareholders' equity			74
Total liabilities and shareholders' equity			(112)
Accounting Standards Update 2014-09 \| Difference between Revenue Guidance in Effect before and after Topic 606 \| Insurance Renewals
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cash and cash equivalents			0
Securities owned, at fair value			0
Receivables from clearing brokers			0
Receivables from other broker-dealers			0
Notes receivable from financial advisors, net			0
Other receivables, net			58,786
Fixed assets, net			0
Restricted cash			0
Intangible assets, net			(23,645)
Goodwill			0
Contract acquisition costs, net			0
Cash surrender value of life insurance			0
Other assets			0
Total assets			35,141
Securities sold, but not yet purchased, at fair value			0
Accrued compensation			0
Commissions and fees payable			29,395
Accounts payable and accrued liabilities			0
Deferred rent			0
Deferred income taxes			1,489
Deferred compensation liability			0
Accrued interest			0
Notes payable			0
Total liabilities			30,884
Commitments and contingencies (Note 11)
Preferred stock			0
Common stock			0
Additional paid-in capital			0
Accumulated deficit			4,257
Total shareholders’ equity of the Company			4,257
Noncontrolling interest			0
Total shareholders' equity			4,257
Total liabilities and shareholders' equity			35,141
Accounting Standards Update 2014-09 \| Difference between Revenue Guidance in Effect before and after Topic 606 \| Costs to obtain or fulfill a contract
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cash and cash equivalents			0
Securities owned, at fair value			0
Receivables from clearing brokers			0
Receivables from other broker-dealers			0
Notes receivable from financial advisors, net			(40,566)
Other receivables, net			0
Fixed assets, net			0
Restricted cash			0
Intangible assets, net			0
Goodwill			0
Contract acquisition costs, net			61,340
Cash surrender value of life insurance			0
Other assets			0
Total assets			20,774
Securities sold, but not yet purchased, at fair value			0
Accrued compensation			0
Commissions and fees payable			0
Accounts payable and accrued liabilities			(1,133)
Deferred rent			0
Deferred income taxes			2,118
Deferred compensation liability			0
Accrued interest			0
Notes payable			0
Total liabilities			985
Commitments and contingencies (Note 11)
Preferred stock			0
Common stock			0
Additional paid-in capital			0
Accumulated deficit			19,778
Total shareholders’ equity of the Company			19,778
Noncontrolling interest			11
Total shareholders' equity			19,789
Total liabilities and shareholders' equity			$ 20,774