Quarterly report pursuant to Section 13 or 15(d)

Notes Payable - Narrative (Details)

Notes Payable - Narrative (Details) - USD ($)									1 Months Ended		9 Months Ended	12 Months Ended
Notes Payable - Narrative (Details) - USD ($)	May 29, 2019	Mar. 06, 2019	Dec. 24, 2018	Aug. 09, 2018	Jun. 22, 2018	May 22, 2018	Dec. 12, 2017	Nov. 21, 2017	Jun. 30, 2018	Feb. 28, 2018	Sep. 30, 2019	Dec. 31, 2018	Apr. 30, 2019	Feb. 06, 2019	Nov. 30, 2018	Aug. 31, 2018
Line of Credit Facility [Line Items]
Notes payable, debt issuance costs											$ 8,660,000	$ 7,086,000
Long-term debt											315,898,000	254,072,000
Shares authorized for repurchase (in shares) (up to)													37,500,000
Fair Value \| Level 2
Line of Credit Facility [Line Items]
Notes payable, net											$ 333,145,000	266,844,000
Senior Notes \| 6.5% Senior notes
Line of Credit Facility [Line Items]
Face amount of debt							$ 76,569,000	$ 72,500,000
Interest rate								6.50%			6.50%
Redemption percentage								100.00%
Option to exercise amount							4,069,000
Notes payable, debt issuance costs							3,313,000
Commissions							$ 1,187,000
Debt sold										$ 25,000,000		$ 6,240,000
Commissions receivable, percentage										2.00%
Senior Notes \| 6.5% Senior notes \| Management and board of directors
Line of Credit Facility [Line Items]
Notes purchased by directors								$ 10,400,000
Senior Notes \| 7% Senior Notes
Line of Credit Facility [Line Items]
Face amount of debt					$ 41,412,000	$ 40,000,000
Interest rate						7.00%					7.00%	7.00%
Redemption percentage						100.00%
Option to exercise amount					1,412,000
Notes payable, debt issuance costs					2,020,000
Commissions					$ 464,000
Debt sold									$ 25,000,000			$ 2,729,000
Commissions receivable, percentage						2.00%
Long-term debt											$ 1,622,000
Senior Notes \| 7.25% Senior Notes
Line of Credit Facility [Line Items]
Face amount of debt				$ 60,000,000
Interest rate				7.25%							7.25%
Redemption percentage				100.00%
Notes payable, debt issuance costs				$ 2,135,000
Commissions				120,000
Proceeds from issuance of debt				$ 60,000,000
Senior Notes \| 7.25% Senior Notes \| Repurchase Agreement
Line of Credit Facility [Line Items]
Face amount of debt			$ 76,350,000
Interest rate			7.25%
Senior Notes \| 7.75% Senior Notes
Line of Credit Facility [Line Items]
Face amount of debt	$ 57,500,000
Interest rate	7.75%										7.75%
Redemption percentage	100.00%
Notes payable, debt issuance costs	$ 2,068,000
Proceeds from issuance of debt	$ 57,500,000
Notes Payable \| Notes payable to Kestler Financial Group's former shareholders \| Kestler Financial Group
Line of Credit Facility [Line Items]
Face amount of debt																$ 5,450,000
Interest rate																4.00%
Notes Payable \| Notes payable to Four Seasons Financial Group's former shareholders \| Four Seasons Financial Group
Line of Credit Facility [Line Items]
Face amount of debt															$ 372,000
Notes Payable \| Promissory notes Interest rate at 3.99% per annum \| Four Seasons Financial Group
Line of Credit Facility [Line Items]
Interest rate															3.99%
Notes Payable \| Promissory notes Interest rate at 4.75% per annum \| Four Seasons Financial Group
Line of Credit Facility [Line Items]
Interest rate															4.75%
Notes Payable \| Notes Payable to Frost former shareholders \| Repurchase Agreement
Line of Credit Facility [Line Items]
Interest rate												7.25%
Redemption percentage											100.00%
Shares authorized for repurchase (in shares) (up to)			50,900,000
Share price (in USD per share)			$ 2.50
Cash used in transaction			$ 50,900,000
Shares of common stock canceled (in shares)			3,610,000
Cash exchanged for cancellation			$ 3,000,000
Term Loan \| Bank Term Loan \| Securities America
Line of Credit Facility [Line Items]
Face amount of debt														$ 7,000,000
Interest rate														5.52%
Long-term debt											$ 5,728,000
Monthly payments		$ 212,000
Interest expense on note											$ 210,000