Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Goodwill and other intangibles	$ 43,298		$ 43,298		$ 43,952
Total assets	2,405,949		2,405,949		2,328,864
Net interest income	20,491	$ 19,562	40,456	$ 38,508
Provision for loan losses	750	750	1,300	1,525
Service fees, security gains and other noninterest income	6,994	6,306	13,514	12,316
Noninterest expense	15,985	14,708	31,253	29,055
Amortization and depreciation expense	719	750	1,428	1,499
INCOME BEFORE INCOME TAXES	10,031	9,660	19,989	18,745
Income taxes	1,488	1,587	3,058	2,946
NET INCOME	8,543	8,073	16,931	15,799
Eliminations And Others
Segment Reporting Information [Line Items]
Goodwill and other intangibles	(822)		(822)		(822)
Total assets	4,330		4,330		4,670
Net interest income	(23)	(23)	(45)	(41)
Provision for loan losses	0	0	0	0
Service fees, security gains and other noninterest income	(87)	(64)	(128)	(125)
Noninterest expense	274	280	413	486
Amortization and depreciation expense	12	12	24	24
INCOME BEFORE INCOME TAXES	(396)	(379)	(610)	(676)
Income taxes	(138)	(136)	(250)	(245)
NET INCOME	(258)	(243)	(360)	(431)
Trust Segment | Operating Segments
Segment Reporting Information [Line Items]
Goodwill and other intangibles	4,105		4,105		4,199
Total assets	12,554		12,554		11,490
Net interest income	40	34	78	65
Provision for loan losses	0	0	0	0
Service fees, security gains and other noninterest income	1,842	1,784	3,740	3,622
Noninterest expense	1,225	1,155	2,488	2,432
Amortization and depreciation expense	52	62	104	125
INCOME BEFORE INCOME TAXES	605	601	1,226	1,130
Income taxes	128	127	258	238
NET INCOME	477	474	968	892
Bank Segment | Operating Segments
Segment Reporting Information [Line Items]
Goodwill and other intangibles	37,626		37,626		38,113
Total assets	2,385,763		2,385,763		2,309,644
Net interest income	20,474	19,551	40,423	38,484
Provision for loan losses	750	750	1,300	1,525
Service fees, security gains and other noninterest income	4,789	4,121	9,094	7,975
Noninterest expense	14,191	12,884	27,719	25,436
Amortization and depreciation expense	615	625	1,220	1,249
INCOME BEFORE INCOME TAXES	9,707	9,413	19,278	18,249
Income taxes	1,474	1,591	3,030	2,944
NET INCOME	8,233	7,822	16,248	15,305
Retirement Consulting Segment | Operating Segments
Segment Reporting Information [Line Items]
Goodwill and other intangibles	2,389		2,389		2,462
Total assets	3,302		3,302		$ 3,060
Net interest income	0	0	0	0
Provision for loan losses	0	0	0	0
Service fees, security gains and other noninterest income	450	465	808	844
Noninterest expense	295	389	633	701
Amortization and depreciation expense	40	51	80	101
INCOME BEFORE INCOME TAXES	115	25	95	42
Income taxes	24	5	20	9
NET INCOME	$ 91	$ 20	$ 75	$ 33