Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Cash flows from operating activities
Net (loss) income	$ (7,461)	$ 17,019	$ 92,912
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Depreciation and amortization	3,312	1,990	1,290
Deferred income taxes	(8,820)	2,239	(30,915)
Net investment income from investments	(5,433)	(17,774)	(6,920)
Gain on the sale of assets	0	0	(8,944)
Stock compensation	7,192	9,397	8,457
Other	46	192	166
Receivables:
Securities borrowed	(90,363)	(594,674)	0
Brokers, dealers and clearing organizations	6,940	(5,405)	(279)
Customers	2,209	780	(2,003)
Affiliates	(3,341)	(4,022)	(71)
Interest, dividends and other	2,810	(468)	681
Trading securities	43,662	499	16,029
Prepaid expenses and other assets	1,505	(483)	979
Changes in operating liabilities:
Securities loaned	91,726	595,717	0
Trading account financial instruments sold, not yet purchased	(38,452)	(2,863)	(14,688)
Accounts payable, accrued expenses and other liabilities	(4,008)	4,235	(3,979)
Accrued compensation and benefits	(21,141)	(16,614)	41,519
Brokers, dealers and clearing organizations	0	(8,702)	5,003
Net cash (used in) provided by operating activities	(19,617)	(18,937)	99,237
Cash flows from investing activities
Purchases of investment securities and other investments	(17,563)	(74,382)	(68,864)
Proceeds from sales of and distributions from investments	40,950	60,681	38,190
Settlement of financial instruments sold, not yet purchased	(288,860)	(208,848)	0
Financial instruments sold, not yet purchased	217,940	301,230	0
Due from brokers, dealers and clearing organizations	84,134	(84,134)	0
Proceeds from sale of assets	0	0	19,294
Purchase of broker-dealer, net of cash acquired	(2,275)	0	0
Purchase of securities lending business	(2,166)	(1,000)	0
Purchases of furniture, equipment, software, and leasehold improvements	(2,261)	(9,509)	(882)
Net cash provided by (used in) investing activities	29,899	(15,962)	(12,262)
Cash flows from financing activities
Repurchases of common stock	(48,332)	(65,917)	(59,358)
Proceeds from sales of common stock and repayments of employee stock purchase plan	2,089	1,805	5,431
Dividends paid	(2,934)	0	0
Net cash used in financing activities	(49,177)	(64,112)	(53,927)
Cash and cash equivalents
Net (decrease) increase in cash and cash equivalents	(38,895)	(99,011)	33,048
Cash and cash equivalents, beginning of period	108,962	207,973	174,925
Cash and cash equivalents, end of period	70,067	108,962	207,973
Supplemental cash flows disclosures
Income tax payments	19	3,339	3,372
Interest payments	35,745	21,775	0
Non-cash investing and financing activities
Leasehold improvement incentives	68	4,434	0
Acquisition of securities lending business - contingent consideration	(637)	4,070	0
Dividends payable	$ 776	$ 0	$ 0