Loans (Narrative) (Details) $ in Thousands		Sep. 30, 2021 USD ($) loan	Dec. 31, 2020 USD ($)
Carrying value of PPP loans		$ 77,400	$ 199,800
Loans Receivable Net Deferred Cost Originated		5,000	1,500
Loans Receivable Net Deferred Premium on Purchased Loans		489	787
Accrued interest receivable on loans		11,100	11,300
Loans pledged as collateral		$ 2,200,000	2,100,000
Number of executed loan modifications due to COVID-19 | loan		654
Balance of executed loan modifications due to COVID-19		$ 728,000
Number of active deferments due to COVID-19 | loan		5
Balance of active deferments due to COVID-19		$ 38,000
Past due loans included in nonaccrual loans		6,900	8,500
Nonaccrual loans with no ACL		4,000	3,000
Residential loans in process of foreclosure		1,500	3,400
Nonaccrual loans current on payment		4,000	4,700
Individually analyzed loans		15,500	18,300
Collateral dependent loans	[1]	$ 4,286,404	4,195,990
Active deferments as % of total loans excl PPP loans		1.00%
Collateral Dependent Individually Analyzed
Collateral dependent loans		$ 7,725	$ 8,444

[1] Includes net unamortized loan origination costs of $5.0 million and $1.5 million, respectively, at September 30, 2021 and December 31, 2020 and net unamortized premiums on purchased loans of $489 thousand and $787 thousand, respectively, at September 30, 2021 and December 31, 2020.