Fair Value Disclosures (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Tax-exempt asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at Beginning of Period	$ 197,027	$ 95,804
Purchases / Additions	0	92,010
Sales / Reductions	(4,353)	0
Realized	0	0
Unrealized	(1,200)	4,030
Balance at End of Period	191,474	191,844
Credit risk transfer securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at Beginning of Period	11,964	0
Purchases / Additions	0	15,044
Sales / Reductions	0	0
Realized	0	(331)
Unrealized	(3,949)	(4,076)
Balance at End of Period	8,015	10,637
Loans Held For Sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at Beginning of Period	7,043	16,415
Purchases / Additions	213	0
Sales / Reductions	(684)	(3,878)
Realized	28	216
Unrealized	94	293
Balance at End of Period	$ 6,694	$ 13,046