Securities (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($) Security	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	$ 1,234,450		$ 1,052,132
Unrealized Gains	16,935		21,431
Unrealized Losses	4,105		1,404
Fair Value	1,247,280		1,072,159
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less Than Twelve Months, Fair Value	305,819		148,169
Less Than Twelve Months, Unrealized Losses	3,865		989
Twelve Months or More, Fair Value	18,816		28,257
Twelve Months or More, Unrealized Losses	240		415
Total, Fair Value	324,635		176,426
Total, Unrealized Losses	4,105		1,404
Available-for-sale, allowance for credit losses	0
Accrued interest receivable	5,100
Credit related charges recognized in earnings	0	$ 0
U.S. Agency [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	8,721		10,456
Unrealized Gains	201		305
Unrealized Losses	12		13
Fair Value	8,910		10,748
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less Than Twelve Months, Fair Value	1,394		1,469
Less Than Twelve Months, Unrealized Losses	3		3
Twelve Months or More, Fair Value	2,219		2,329
Twelve Months or More, Unrealized Losses	9		10
Total, Fair Value	3,613		3,798
Total, Unrealized Losses	$ 12		13
Number of securities with market fair value less than amortized cost | Security	25
U.S. Agency Residential Mortgage-Backed [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	$ 399,290		340,224
Unrealized Gains	3,315		4,951
Unrealized Losses	2,185		593
Fair Value	400,420		344,582
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less Than Twelve Months, Fair Value	185,615		96,839
Less Than Twelve Months, Unrealized Losses	2,184		592
Twelve Months or More, Fair Value	36		83
Twelve Months or More, Unrealized Losses	1		1
Total, Fair Value	185,651		96,922
Total, Unrealized Losses	$ 2,185		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	$ 11,516		6,869
Unrealized Gains	194		326
Unrealized Losses	6		0
Fair Value	11,704		7,195
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less Than Twelve Months, Fair Value	646
Less Than Twelve Months, Unrealized Losses	6
Twelve Months or More, Fair Value	0
Twelve Months or More, Unrealized Losses	0
Total, Fair Value	646
Total, Unrealized Losses	$ 6
Number of securities with market fair value less than amortized cost | Security	2
Private Label Mortgage-Backed [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	$ 41,624		41,429
Unrealized Gains	1,261		1,539
Unrealized Losses	68		139
Fair Value	42,817		42,829
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less Than Twelve Months, Fair Value	2,053		11,838
Less Than Twelve Months, Unrealized Losses	25		95
Twelve Months or More, Fair Value	3,662		2,050
Twelve Months or More, Unrealized Losses	43		44
Total, Fair Value	5,715		13,888
Total, Unrealized Losses	$ 68		139
Number of securities with market fair value less than amortized cost | Security	11
Other Asset Backed [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	$ 226,812		252,596
Unrealized Gains	1,810		1,796
Unrealized Losses	92		211
Fair Value	228,530		254,181
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less Than Twelve Months, Fair Value	8,407		7,142
Less Than Twelve Months, Unrealized Losses	17		25
Twelve Months or More, Fair Value	10,465		21,197
Twelve Months or More, Unrealized Losses	75		186
Total, Fair Value	18,872		28,339
Total, Unrealized Losses	$ 92		211
Number of securities with market fair value less than amortized cost | Security	20
Obligations of States and Political Subdivisions [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	$ 438,721		315,780
Unrealized Gains	7,274		8,691
Unrealized Losses	1,307		178
Fair Value	444,688		324,293
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less Than Twelve Months, Fair Value	87,301		28,957
Less Than Twelve Months, Unrealized Losses	1,307		177
Twelve Months or More, Fair Value	0		800
Twelve Months or More, Unrealized Losses	0		1
Total, Fair Value	87,301		29,757
Total, Unrealized Losses	$ 1,307		178
Number of securities with market fair value less than amortized cost | Security	107
Corporate [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	$ 105,293		82,307
Unrealized Gains	2,866		3,807
Unrealized Losses	336		97
Fair Value	107,823		86,017
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less Than Twelve Months, Fair Value	20,403		1,924
Less Than Twelve Months, Unrealized Losses	323		97
Twelve Months or More, Fair Value	560		0
Twelve Months or More, Unrealized Losses	13		0
Total, Fair Value	20,963		1,924
Total, Unrealized Losses	$ 336		97
Number of securities with market fair value less than amortized cost | Security	19
Trust Preferred [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	$ 1,973		1,971
Unrealized Gains	0		0
Unrealized Losses	99		173
Fair Value	1,874		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	1,874		1,798
Twelve Months or More, Unrealized Losses	99		173
Total, Fair Value	1,874		1,798
Total, Unrealized Losses	$ 99		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	920
Foreign Government [Member]
Available-for-sale Securities, Amortized Cost Basis [Abstract]
Amortized cost	500		500
Unrealized Gains	14		16
Unrealized Losses	0		0
Fair Value	$ 514		$ 516