Securities (Schedule of Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Amortized Cost
Due in one year or less	$ 2,150
Due after one year through five years	22,212
Due after five years through ten years	68,621
Due after ten years	720,105
Amortized Cost	1,681,122	$ 1,172,175
Fair Value
Due in one year or less	2,173
Due after one year through five years	23,391
Due after five years through ten years	73,304
Due after ten years	734,585
Fair Value	1,696,225	1,217,852
MBS/CMO
Amortized Cost
Securities without single maturity	728,789
Amortized Cost	728,789	535,526
Fair Value
Securities without single maturity	726,632
Fair Value	726,632	548,307
US Gov't Sponsored Entities & Agencies
Amortized Cost
Securities without single maturity	139,245
Amortized Cost	139,245	88,376
Fair Value
Securities without single maturity	136,140
Fair Value	$ 136,140	$ 88,298

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