Securities, Available for Sale, Gross Unrealized Losses and Fair Values (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($) Security	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	$ 1,332,054		$ 1,052,132
Unrealized Gains	19,811		21,431
Unrealized Losses	3,487		1,404
Fair Value	1,348,378		1,072,159
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less Than Twelve Months, Fair Value	287,991		148,169
Less Than Twelve Months, Unrealized Losses	3,086		989
Twelve Months or More, Fair Value	26,261		28,257
Twelve Months or More, Unrealized Losses	401		415
Total, Fair Value	314,252		176,426
Total, Unrealized Losses	3,487		1,404
Available-for-sale, allowance for credit losses	0
Accrued interest receivable	5,700
Credit related charges recognized in earnings	0	$ 0
U.S. Agency [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	13,278		10,456
Unrealized Gains	187		305
Unrealized Losses	47		13
Fair Value	13,418		10,748
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less Than Twelve Months, Fair Value	5,071		1,469
Less Than Twelve Months, Unrealized Losses	44		3
Twelve Months or More, Fair Value	1,382		2,329
Twelve Months or More, Unrealized Losses	3		10
Total, Fair Value	6,453		3,798
Total, Unrealized Losses	$ 47		13
Number of securities with market fair value less than amortized cost | Security	14
U.S. Agency Residential Mortgage-Backed [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	$ 337,140		340,224
Unrealized Gains	2,810		4,951
Unrealized Losses	2,090		593
Fair Value	337,860		344,582
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less Than Twelve Months, Fair Value	135,320		96,839
Less Than Twelve Months, Unrealized Losses	1,923		592
Twelve Months or More, Fair Value	19,297		83
Twelve Months or More, Unrealized Losses	167		1
Total, Fair Value	154,617		96,922
Total, Unrealized Losses	$ 2,090		593
Number of securities with market fair value less than amortized cost | Security	57
U.S. Agency Commercial Mortgage-Backed [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	$ 18,473		6,869
Unrealized Gains	161		326
Unrealized Losses	26		0
Fair Value	18,608		7,195
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less Than Twelve Months, Fair Value	5,367
Less Than Twelve Months, Unrealized Losses	26
Twelve Months or More, Fair Value	0
Twelve Months or More, Unrealized Losses	0
Total, Fair Value	5,367
Total, Unrealized Losses	$ 26
Number of securities with market fair value less than amortized cost | Security	13
Private Label Mortgage-Backed [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	$ 81,154		41,429
Unrealized Gains	1,271		1,539
Unrealized Losses	114		139
Fair Value	82,311		42,829
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less Than Twelve Months, Fair Value	18,628		11,838
Less Than Twelve Months, Unrealized Losses	88		95
Twelve Months or More, Fair Value	2,110		2,050
Twelve Months or More, Unrealized Losses	26		44
Total, Fair Value	20,738		13,888
Total, Unrealized Losses	$ 114		139
Number of securities with market fair value less than amortized cost | Security	21
Other Asset Backed [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	$ 174,488		252,596
Unrealized Gains	1,653		1,796
Unrealized Losses	20		211
Fair Value	176,121		254,181
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less Than Twelve Months, Fair Value	8,161		7,142
Less Than Twelve Months, Unrealized Losses	9		25
Twelve Months or More, Fair Value	989		21,197
Twelve Months or More, Unrealized Losses	11		186
Total, Fair Value	9,150		28,339
Total, Unrealized Losses	$ 20		211
Number of securities with market fair value less than amortized cost | Security	10
Obligations of States and Political Subdivisions [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	$ 555,155		315,780
Unrealized Gains	9,983		8,691
Unrealized Losses	916		178
Fair Value	564,222		324,293
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less Than Twelve Months, Fair Value	88,064		28,957
Less Than Twelve Months, Unrealized Losses	871		177
Twelve Months or More, Fair Value	567		800
Twelve Months or More, Unrealized Losses	45		1
Total, Fair Value	88,631		29,757
Total, Unrealized Losses	$ 916		178
Number of securities with market fair value less than amortized cost | Security	193
Corporate [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	$ 149,893		82,307
Unrealized Gains	3,736		3,807
Unrealized Losses	126		97
Fair Value	153,503		86,017
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less Than Twelve Months, Fair Value	27,380		1,924
Less Than Twelve Months, Unrealized Losses	125		97
Twelve Months or More, Fair Value	90		0
Twelve Months or More, Unrealized Losses	1		0
Total, Fair Value	27,470		1,924
Total, Unrealized Losses	$ 126		97
Number of securities with market fair value less than amortized cost | Security	22
Trust Preferred [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	$ 1,974		1,971
Unrealized Gains	0		0
Unrealized Losses	148		173
Fair Value	1,826		1,798
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less Than Twelve Months, Fair Value	0		0
Less Than Twelve Months, Unrealized Losses	0		0
Twelve Months or More, Fair Value	1,826		1,798
Twelve Months or More, Unrealized Losses	148		173
Total, Fair Value	1,826		1,798
Total, Unrealized Losses	$ 148		173
Number of securities with market fair value less than amortized cost | Security	2
Number of issues rated as investment grade | Security	1
Number of securities not rated | Security	1
Non-rated securities, amortized cost	$ 1,000
Fair value of non-rated trust preferred securities	860
Foreign Government [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	499		500
Unrealized Gains	10		16
Unrealized Losses	0		0
Fair Value	$ 509		$ 516