Consolidated Statements of Cash Flows - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Cash Flows [Abstract]
Increase (Decrease) in Deposit Assets	$ 3,717,000	$ 7,077,000
Cash flows from operating activities
Net loss	(4,751,000)	(3,909,000)
Non-cash items included in net income:
Depreciation and amortization of furniture, equipment and leasehold improvements	1,432,000	1,534,000
Deferred income taxes	807,000	2,735,000
Amortization of notes receivable	2,782,000	3,431,000
Amortization of debt issuance costs	121,000	121,000
Amortization of mortgage servicing rights	0	782,000
Provision for (reversal of) credit losses	(33,000)	28,000
Share-based compensation	739,000	1,189,000
Excess Tax Benefit from Share-based Compensation, Operating Activities	0	(741,000)
Decrease (increase) in operating assets:
Receivable from brokers, dealers and clearing organizations	(17,651,000)	97,550,000
Receivable from customers	17,335,000	48,696,000
Income tax receivable	(2,511,000)	(6,324,000)
Securities purchased under agreements to resell	20,110,000	206,499,000
Securities owned	(292,599,000)	(301,389,000)
Notes receivable	(6,491,000)	(3,451,000)
Loans held for sale	0	46,702,000
Mortgage servicing rights	0	(638,000)
Other assets	(5,860,000)	(13,625,000)
Increase (decrease) in operating liabilities:
Drafts payable	(6,445,000)	(10,348,000)
Payable to brokers, dealers and clearing organizations	(46,185,000)	43,333,000
Payable to customers	54,402,000	(73,276,000)
Securities sold under agreements to repurchase	78,006,000	(121,693,000)
Securities sold but not yet purchased	214,422,000	144,459,000
Accrued compensation	(49,200,000)	(56,760,000)
Accounts payable and other liabilities	3,301,000	(38,600,000)
Cash used in operating activities	(41,986,000)	(40,772,000)
Cash flows from investing activities
Purchase of furniture, equipment and leasehold improvements	(1,550,000)	(1,762,000)
Cash used in investing activities	(1,550,000)	(1,762,000)
Cash flows from financing activities
Cash dividends paid on Class A non-voting and Class B voting common stock	(1,480,000)	(1,476,000)
Cash dividends paid to noncontrolling interest	(816,000)	0
Repurchase of Class A non-voting common stock for cancellation	(4,357,000)	(3,634,000)
Payments for employee taxes withheld related to vested share-based awards	(2,203,000)	(1,341,000)
Increase in bank call loans, net	49,900,000	48,100,000
Cash provided by financing activities	41,044,000	41,649,000
Net decrease in cash and cash equivalents	(2,492,000)	(885,000)
Cash and cash equivalents, beginning of period	64,913,000	63,364,000
Cash and cash equivalents, end of period	62,421,000	62,479,000
Schedule of non-cash financing activities
Employee share plan issuance	3,857,000	5,463,000
Supplemental disclosure of cash flow information
Cash paid during the period for interest	2,023,000	1,788,000
Cash paid during the period for income taxes, net	$ 503,000	$ 181,000