Operating Expenses - Components of Operating Expenses (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other Income and Expenses [Abstract]
Fixed compensation expense									$ 24,332	$ 35,093	$ 29,057
Variable compensation expense									16,581	12,606	14,863
Equity compensation expense									9,093	11,921	9,750
Total compensation expense									50,006	59,620	53,670
Systems and consulting									9,037	10,212	11,654
Loan acquisition costs									5,744	10,326	8,207
Office costs									4,550	5,270	5,011
Accounting and legal									3,658	4,837	5,244
Corporate costs									2,106	2,049	2,237
Other operating expenses									3,284	5,102	4,100
Operating expenses before restructuring charges									78,385	97,416	90,123
Costs incurred and expensed				$ 10,401					10,401	0	0
Total Operating Expenses	$ 17,824	$ 20,355	$ 20,155	30,452	$ 22,638	$ 24,497	$ 25,218	$ 25,063	88,786	97,416	90,123
Restructuring Cost and Reserve [Line Items]
Costs incurred and expensed				10,401					10,401	$ 0	$ 0
Fixed Compensation Expense
Other Income and Expenses [Abstract]
Costs incurred and expensed									5,000
Restructuring Cost and Reserve [Line Items]
Costs incurred and expensed									5,000
Equity Compensation Expense
Other Income and Expenses [Abstract]
Costs incurred and expensed									3,000
Restructuring Cost and Reserve [Line Items]
Costs incurred and expensed									3,000
Contract Termination Costs
Other Income and Expenses [Abstract]
Costs incurred and expensed				2,000					1,655
Restructuring Cost and Reserve [Line Items]
Costs incurred and expensed				$ 2,000					$ 1,655