Certain Transfers of Financial Assets Certain Transfers of Financial Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Outstanding balance(1):
Beginning balance	$ 1,949,785	$ 1,012,580
Loans purchased	10,183,057	6,753,709
Payments and loans sold	(9,564,480)	(5,816,504)
Ending balance	2,568,362	1,949,785
Fair value adjustment:
Increase/(decrease) to fair value	(10,917)	21,265
Fair value over (under) outstanding balance	8,772	19,689	$ (1,576)
Loans held for sale	2,577,134	1,969,474
Small Business Administration Loans [Member]
Fair value adjustment:
Fair value over (under) outstanding balance	$ 5,800	$ 299	$ 3,300