Regulatory Requirements - Regulatory Capital Amounts And Ratios Compared To Regulatory Requirements (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier 1 Capital (to risk-weighted assets), amount	$ 651,974	$ 636,141
Common Equity Tier 1 Capital (to risk-weighted assets), ratio	16.35%	17.17%
Common Equity Tier 1 Capital (to risk-weighted assets), for capital adequacy purposes amount	$ 179,439	$ 166,717
Common Equity Tier 1 Capital (to risk-weighted assets), for capital adequacy purposes ratio	4.50%	4.50%
Common Equity Tier 1 Capital (to risk-weighted assets), for well capitalized under prompt corrective action provisions amount	$ 259,189	$ 240,814
Common Equity Tier 1 Capital (to risk-weighted assets), for well capitalized under prompt corrective action provisions ratio	6.50%	6.50%
Tier 1 capital (core) (to adjusted total assets), amount	$ 651,974	$ 636,141
Tier 1 capital (core) (to adjusted total assets), ratio	13.37%	14.82%
Tier 1 capital (core) (to adjusted total assets), for capital adequacy purposes amount	$ 195,018	$ 171,724
Tier 1 capital (core) (to adjusted total assets), for capital adequacy purposes ratio	4.00%	4.00%
Tier 1 capital (core) (to adjusted total assets), for well capitalized under prompt corrective action provisions amount	$ 243,772	$ 214,656
Tier 1 capital (core) (to adjusted total assets), for well capitalized under prompt corrective action provisions ratio	5.00%	5.00%
Tier 1 capital (to risk-weighted assets), amount	$ 651,974	$ 636,141
Tier 1 capital (to risk-weighted assets), ratio	16.35%	17.17%
Tier 1 capital (to risk-weighted assets), for capital adequacy purposes amount	$ 239,251	$ 222,290
Tier 1 capital (to risk-weighted assets), for capital adequacy purposes ratio	6.00%	6.00%
Tier 1 capital (to risk-weighted assets) for well capitalized under prompt corrective action provisions amount	$ 319,002	$ 296,386
Tier 1 capital (to risk-weighted assets) for well capitalized under prompt corrective action provisions ratio	8.00%	8.00%
Total capital (to risk-weighted assets), actual	$ 681,467	$ 664,190
Total capital (to risk-weighted assets), ratio	17.09%	17.93%
Total capital (to risk-weighted assets), for capital adequacy purposes amount	$ 319,002	$ 296,386
Total capital (to risk-weighted assets), for capital adequacy purposes ratio	8.00%	8.00%
Total capital (to risk-weighted assets), for well capitalized under prompt corrective action provisions amount	$ 398,752	$ 370,483
Total capital (to risk-weighted assets), for well capitalized under prompt corrective action provisions ratio	10.00%	10.00%
Subsidiaries
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier 1 Capital (to risk-weighted assets), amount	$ 598,462	$ 592,815
Common Equity Tier 1 Capital (to risk-weighted assets), ratio	14.99%	16.00%
Common Equity Tier 1 Capital (to risk-weighted assets), for capital adequacy purposes amount	$ 179,626	$ 166,742
Common Equity Tier 1 Capital (to risk-weighted assets), for capital adequacy purposes ratio	4.50%	4.50%
Common Equity Tier 1 Capital (to risk-weighted assets), for well capitalized under prompt corrective action provisions amount	$ 259,459	$ 240,850
Common Equity Tier 1 Capital (to risk-weighted assets), for well capitalized under prompt corrective action provisions ratio	6.50%	6.50%
Tier 1 capital (core) (to adjusted total assets), amount	$ 598,462	$ 592,815
Tier 1 capital (core) (to adjusted total assets), ratio	12.28%	13.81%
Tier 1 capital (core) (to adjusted total assets), for capital adequacy purposes amount	$ 194,954	$ 171,663
Tier 1 capital (core) (to adjusted total assets), for capital adequacy purposes ratio	4.00%	4.00%
Tier 1 capital (core) (to adjusted total assets), for well capitalized under prompt corrective action provisions amount	$ 243,692	$ 214,579
Tier 1 capital (core) (to adjusted total assets), for well capitalized under prompt corrective action provisions ratio	5.00%	5.00%
Tier 1 capital (to risk-weighted assets), amount	$ 598,462	$ 592,815
Tier 1 capital (to risk-weighted assets), ratio	14.99%	16.00%
Tier 1 capital (to risk-weighted assets), for capital adequacy purposes amount	$ 239,501	$ 222,323
Tier 1 capital (to risk-weighted assets), for capital adequacy purposes ratio	6.00%	6.00%
Tier 1 capital (to risk-weighted assets) for well capitalized under prompt corrective action provisions amount	$ 319,334	$ 296,430
Tier 1 capital (to risk-weighted assets) for well capitalized under prompt corrective action provisions ratio	8.00%	8.00%
Total capital (to risk-weighted assets), actual	$ 627,955	$ 620,863
Total capital (to risk-weighted assets), ratio	15.73%	16.76%
Total capital (to risk-weighted assets), for capital adequacy purposes amount	$ 319,334	$ 296,430
Total capital (to risk-weighted assets), for capital adequacy purposes ratio	8.00%	8.00%
Total capital (to risk-weighted assets), for well capitalized under prompt corrective action provisions amount	$ 399,168	$ 370,538
Total capital (to risk-weighted assets), for well capitalized under prompt corrective action provisions ratio	10.00%	10.00%