Condensed Consolidated Statement of Operations (Parenthetical) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019		Dec. 31, 2018
Management Fee Expense, Rebates	$ 509	$ 503	$ 508	$ 447	$ 400	$ 400	$ 300	$ 300	$ 2,000	[1]
Interest income	45,353	39,985	38,547	36,016	35,694	35,300	31,941	28,092	159,901		$ 131,027	[2]
Interest Expense	$ 21,205	$ 19,954	$ 19,702	$ 17,618	16,083	15,678	13,383	11,562	$ 78,479		56,707
Management fee rebate											1,380
Consolidated Entities [Member]
Interest income					2,100	1,300	1,300	1,300			6,000
Interest Expense					$ 1,200	$ 700	$ 800	$ 900			$ 3,600

[1] See Note 13 for further details on management fee rebates.

[2] Includes interest income and interest expense of a consolidated securitization trust of $6.0 million and $3.6 million, respectively, for the year ended December 31, 2018. See Note 6 for further details on the Company's consolidated securitization trust.