Annual report pursuant to Section 13 and 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	3 Months Ended
	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cash and cash equivalents	$ 182,693	$ 172,103	$ 172,103	$ 98,930
Securities owned, at fair value	10,923	3,881	3,881
Receivables from clearing brokers	24,068	48,543	48,543
Receivables from other broker-dealers	7,078	2,822	2,822
Notes receivable from financial advisors, net	5,809	6,803	47,369
Other receivables, net	133,242	119,356	60,707
Fixed assets, net	29,994	23,621	23,621
Restricted cash	6,588	760	760	1,011
Intangible assets, net	73,064	79,966	103,611
Goodwill	126,079	124,210	124,210	124,031
Contract acquisition costs, net	80,726	61,340	0
Cash surrender value of life insurance	11,406	12,711	12,711
Income taxes receivable	2,156		0
Other assets	47,078	31,712	31,687
Total assets	740,904	687,828	632,025	546,003
Securities sold, but not yet purchased, at fair value	2,575	231	231
Accrued compensation	39,192	33,233	33,343
Commissions and fees payable	105,306	96,616	67,221
Accounts payable and accrued liabilities	48,813	39,241	40,478
Deferred rent	2,956	2,151	2,151
Deferred income taxes	14,068		2,968
Deferred income taxes	35,188	5,938	26,518
Deferred compensation liability	20,622	18,161	18,161
Accrued interest	123	232	232
Notes payable	254,072	96,849	96,849
Total liabilities	487,727	292,652	261,634
Commitments and contingencies
Preferred stock	2	2	2
Common stock	14	20	20
Additional paid-in capital	344,356	520,135	520,135
Accumulated deficit	(91,246)	(125,004)	(149,778)
Total shareholders' equity of the Company	253,126	395,153	370,379
Noncontrolling interest	51	23	12
Total shareholders' equity	253,177	395,176	370,391	$ 362,501	$ 376,031
Total liabilities and shareholders' equity	740,904	$ 687,828	632,025
Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings adjustment	665
Contract acquisition costs, net			(40,566)
As Reported
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cash and cash equivalents	182,693		172,103
Securities owned, at fair value	10,923		3,881
Receivables from clearing brokers	24,068		48,543
Receivables from other broker-dealers	7,078		2,822
Notes receivable from financial advisors, net	57,417		47,369
Other receivables, net	69,209		60,707
Fixed assets, net	29,994		23,621
Restricted cash	6,588		760
Intangible assets, net	91,454		103,611
Goodwill	126,079		124,210
Contract acquisition costs, net	0		0
Cash surrender value of life insurance	11,406		12,711
Income taxes receivable	0
Other assets	46,578		31,687
Total assets			632,025
Securities sold, but not yet purchased, at fair value	2,575		231
Accrued compensation	39,257		33,343
Commissions and fees payable	73,452		67,221
Accounts payable and accrued liabilities	41,026		40,478
Deferred rent	2,956		2,151
Deferred income taxes	9,742
Deferred income taxes			2,968
Deferred compensation liability	20,622		18,161
Accrued interest	123		232
Notes payable	254,072		96,849
Total liabilities			261,634
Preferred stock	2		2
Common stock	14		20
Additional paid-in capital	344,356		520,135
Accumulated deficit	(124,750)		(149,778)
Total shareholders' equity of the Company	219,622		370,379
Noncontrolling interest	40		12
Total shareholders' equity	219,662		370,391
Total liabilities and shareholders' equity	663,487		632,025
Adjustments \| Accounting Standards Update 2014-09
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	(51,608)
Other receivables, net	64,033
Fixed assets, net	0
Restricted cash	0
Intangible assets, net	(18,390)
Goodwill	0
Contract acquisition costs, net	80,726
Cash surrender value of life insurance	0
Income taxes receivable	2,156
Other assets	500
Securities sold, but not yet purchased, at fair value	0
Accrued compensation	(65)
Commissions and fees payable	31,854
Accounts payable and accrued liabilities	7,787
Deferred rent	0
Deferred income taxes	4,326
Deferred compensation liability	0
Accrued interest	0
Notes payable	0
Preferred stock	0
Common stock	0
Additional paid-in capital	0
Accumulated deficit	33,504
Total shareholders' equity of the Company	33,504
Noncontrolling interest	11
Total shareholders' equity	33,515
Total liabilities and shareholders' equity	77,417
Investment Banking \| As Reported \| Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total assets	663,487
Total liabilities	443,825
Investment Banking \| Adjustments \| Accounting Standards Update 2014-09
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)
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)
Insurance Renewals \| Adjustments \| Accounting Standards Update 2014-09
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			1,462
Deferred compensation liability			0
Accrued interest			0
Notes payable			0
Total liabilities			30,857
Preferred stock			0
Common stock			0
Additional paid-in capital			0
Accumulated deficit			4,284
Total shareholders' equity of the Company			4,284
Noncontrolling interest			0
Total shareholders' equity			4,284
Total liabilities and shareholders' equity			35,141
Costs to obtain or fulfill a contract \| Adjustments \| Accounting Standards Update 2014-09
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
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	77,417		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			1,480
Deferred compensation liability			0
Accrued interest			0
Notes payable			0
Total liabilities	$ 43,902		347
Preferred stock			0
Common stock			0
Additional paid-in capital			0
Accumulated deficit			20,416
Total shareholders' equity of the Company			20,416
Noncontrolling interest			11
Total shareholders' equity			20,427
Total liabilities and shareholders' equity			$ 20,774