Interest Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Banking and Thrift, Interest [Abstract]
Interest on unpaid principal balance	$ 300,713	$ 227,579	$ 172,472
Interest on deposits	171	408	70
Amortization of net deferred origination costs	(36,040)	(32,939)	(27,267)
Total interest income	$ 264,844	$ 195,048	$ 145,275