Investment Securities (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Schedule of Investments [Line Items]
Other than Temporary Impairment Losses, Investments			$ 0	$ 0
Asset backed securities mortgage portfolio, term			15 years
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			21.00%
Debt Securities, Available-for-sale, Amortized Cost	$ 1,035,743		$ 1,035,743		$ 1,187,499
Debt Securities, Available-for-sale, Realized Gain (Loss)	3,313	$ (607)	3,313	(607)
Debt Securities, Available-for-sale, Realized Gain				18
Debt Securities, Available-for-sale, Realized Loss				625
Securities sold at a gain [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	55,500	5,300	55,500	5,300
Securities sold at a loss [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		$ 51,700		$ 51,700
U.S. Government Sponsored Entities Asset-Backed Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	755,372		755,372		884,571
Collateral Pledged [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Restricted	$ 658,000		$ 658,000		$ 585,000