Securities (Schedule of Securities by Contractual Maturity) (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Amortized Cost
Due in one year or less	$ 5,739,000
Due after one year through five years	17,354,000
Due after five years through ten years	66,272,000
Due after ten years	512,181,000
Amortized Cost	1,367,856,000	$ 1,172,175,000
Fair Value
Due in one year or less	5,770,000
Due after one year through five years	18,027,000
Due after five years through ten years	70,572,000
Due after ten years	529,479,000
Fair Value	1,385,873,000	1,217,852,000
MBS/CMO
Amortized Cost
Securities without single maturity	654,447,000
Amortized Cost	654,447,000	535,526,000
Fair Value
Securities without single maturity	653,449,000
Fair Value	653,449,000	548,307,000
US Gov't Sponsored Entities & Agencies
Amortized Cost
Securities without single maturity	111,863,000
Amortized Cost	111,863,000	88,376,000
Fair Value
Securities without single maturity	108,576,000
Fair Value	$ 108,576,000	$ 88,298,000