Consolidated Statements of Income and Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Interest and dividend income
Interest and fees on loans (includes tax-exempt income of $1,102,000 in 2021, $1,170,000 in 2020, and $1,302,000 in 2019)	$ 62,195	$ 59,059	$ 59,239
Interest on deposits with other banks	72	96	188
Interest and dividends on investments (includes tax-exempt income of $7,644,000 in 2021, $7,617,000 in 2020, and $7,333,000 in 2019)	14,814	17,964	19,224
Total interest and dividend income	77,081	77,119	78,651
Interest expense
Interest on deposits	7,314	14,139	23,268
Interest on borrowed funds	3,464	3,147	2,890
Total interest expense	10,778	17,286	26,158
Net interest income	66,303	59,833	52,493
Provision (credit) for loan losses	(375)	6,050	1,250
Net interest income after provision (credit) for loan losses	66,678	53,783	51,243
Non-interest income
Net securities gains	23	1,155	224
Other operating income	2,819	2,432	2,659
Non-interest income	19,383	18,119	14,189
Non-interest expense
Salaries and employee benefits	21,152	20,388	18,396
Occupancy expense	2,841	2,762	2,558
Furniture and equipment expense	4,788	4,799	3,990
FDIC insurance premiums	824	738	439
Acquisition-related costs	0	310	0
Amortization of identified intangibles	69	43	43
Other operating expense	12,474	10,612	9,746
Total non-interest expense	42,148	39,652	35,172
Income before income taxes	43,913	32,250	30,260
Applicable tax expense	7,644	5,121	4,735
Net income	$ 36,269	$ 27,129	$ 25,525
Basic earnings per common share (in usd per share)	$ 3.33	$ 2.50	$ 2.36
Diluted earnings per common share (in usd per share)	$ 3.30	$ 2.48	$ 2.34
Other comprehensive income (loss), net of tax
Net unrealized gain (loss) on securities available for sale	$ (6,727)	$ 1,352	$ 8,708
Net unrealized gain on securities transferred from available for sale to held to maturity, net of amortization	46	49	15
Net gain (loss) on cash flow hedging derivative instruments	4,932	(5,029)	(1,341)
Net unrecognized gain (loss) on postretirement benefits	77	4	(13)
Other comprehensive gain (loss)	(1,672)	(3,624)	7,369
Comprehensive income	34,597	23,505	32,894
Fiduciary and investment management income
Non-interest income
Non-interest income	4,529	3,660	3,318
Service charges on deposit accounts
Non-interest income
Non-interest income	1,568	1,648	2,330
Mortgage origination and servicing income
Non-interest income
Non-interest income	5,236	5,085	1,909
Debit card income
Non-interest income
Non-interest income	$ 5,208	$ 4,139	$ 3,749