Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Interest Income
Loans, including fees	$ 85,830	$ 81,159	$ 68,799
Investment securities - Taxable	5,576	4,670	4,773
Investment securities -Exempt from federal income taxes	798	1,234	1,356
Other	1,096	639	709
Total interest income	93,300	87,702	75,637
Interest Expense
Deposits	13,334	6,991	3,520
Short-term borrowings	1,805	1,896	942
Long-term debt	3,610	3,591	3,505
Total interest expense	18,749	12,478	7,967
Net interest income	74,551	75,224	67,670
Provision for loan losses	7,312	8,610	3,280
Net interest income after provision for loan losses	67,239	66,614	64,390
Noninterest Income
Retirement and benefit services	63,811	63,316	62,390
Wealth management	15,502	14,900	13,953
Mortgage banking	25,805	17,630	19,748
Service charges on deposit accounts	1,772	1,808	1,854
Net gains (losses) on investment securities	357	85	(13)
Other	6,947	5,010	5,113
Total noninterest income	114,194	102,749	103,045
Noninterest Expense
Compensation	74,018	69,403	67,576
Employee taxes and benefits	19,456	17,866	16,490
Occupancy and equipment expense	10,751	11,086	10,892
Business services, software and technology expense	16,381	14,525	12,976
Intangible amortization expense	4,081	4,638	5,623
Professional fees and assessments	4,011	5,098	6,158
Marketing and business development	3,162	3,459	3,271
Supplies and postage	2,722	2,737	2,609
Travel	1,787	1,738	1,530
Mortgage and lending expenses	2,853	2,153	2,235
Other	3,315	3,622	5,560
Total noninterest expense	142,537	136,325	134,920
Income before income taxes	38,896	33,038	32,515
Income tax expense	9,356	7,172	17,514
Net income	$ 29,540	$ 25,866	$ 15,001
Basic earnings per common share	$ 1.96	$ 1.88	$ 1.10
Diluted earnings per common share	1.91	1.84	1.07
Dividends declared per common share	$ 0.57	$ 0.53	$ 0.48
Average common shares outstanding	14,736	13,763	13,653
Diluted average common shares outstanding	15,093	14,063	14,007