Interest Expense - Schedule of Components of Interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt securities:
Interest expense	$ 114,129	$ 103,371	$ 126,927
Senior Notes
Debt securities:
Interest expense	31,804	31,280	29,806
Match Funded Liabilities
Debt securities:
Interest expense	26,902	31,870	47,624
Other Secured Borrowings
Debt securities:
Interest expense	46,278	35,412	45,099
Financing Liabilities | Other Financing Liabilities With Unrelated Parties
Debt securities:
Interest expense	0	66	635
Other
Debt securities:
Interest expense	$ 9,145	$ 4,743	$ 3,763