Regulatory Capital - Summary of Regulatory Capital Requirement (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital (to risk-weighted assets), Actual, Amount	$ 551,215	$ 548,364
Total capital (to risk-weighted assets), Actual, Ratio	13.69%	13.95%
Total capital (to risk-weighted assets), For capital adequacy purposes, Amount	$ 322,112	$ 314,395
Total capital (to risk-weighted assets), For capital adequacy purposes, Ratio	8.00%	8.00%
Total capital (to risk-weighted assets), Required for capital1 adequacy purposes with capital buffer, Amount	$ 422,773	$ 412,644
Total capital (to risk-weighted assets), Required for capital1 adequacy purposes with capital buffer, Ratio	10.50%	10.50%
Tier 1 capital (to average assets), Actual, Amount	$ 514,493	$ 530,643
Tier 1 capital (to average assets), Actual, Ratio	12.78%	13.50%
Tier 1 capital (to average assets), For capital adequacy purposes, Amount	$ 241,546	$ 235,796
Tier 1 capital (to average assets), For capital adequacy purpose, Ratio	6.00%	6.00%
Tier 1 capital (to average assets), Required for capital1 adequacy purposes with capital buffer, Amount	$ 342,190	$ 334,044
Tier 1 capital (to average assets), Required for capital1 adequacy purposes with capital buffer, Ratio	8.50%	8.50%
Common equity tier 1 capital, Actual Amount	$ 457,000	$ 473,150
Common equity tier 1 capital, Actual Ratio	11.35%	12.04%
Common equity tier 1 capital,For capital adequacy purposes, Amount	$ 181,189	$ 176,846
Common equity tier 1 capital, For capital adequacy purpose, Ratio	4.50%	4.50%
Common equity tier 1 capital (to risk-weighted assets), Required for capital1 adequacy purposes with capital buffer, Amount	$ 281,850	$ 275,094
Common equity tier 1 capital (to risk-weighted assets), Required for capital1 adequacy purposes with capital buffer, Ratio	7.00%	7.00%
Tier 1 capital (to average assets), Actual, Amount	$ 514,493	$ 530,643
Tier 1 capital (to average assets), Actual, Ratio	10.14%	10.50%
Tier 1 capital (to average assets), For capital adequacy purposes, Amount	$ 202,956	$ 202,111
Tier 1 capital (to average assets), For capital adequacy purpose, Ratio	4.00%	4.00%
Tier 1 capital (to average assets), Required for capital1 adequacy purposes with capital buffer, Amount	$ 202,956	$ 202,111
Tier 1 capital (to average assets), Required for capital1 adequacy purposes with capital buffer, Ratio	4.00%	4.00%
Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital (to risk-weighted assets), Actual, Amount	$ 513,248	$ 497,227
Total capital (to risk-weighted assets), Actual, Ratio	12.73%	12.65%
Total capital (to risk-weighted assets), For capital adequacy purposes, Amount	$ 322,544	$ 314,452
Total capital (to risk-weighted assets), For capital adequacy purposes, Ratio	8.00%	8.00%
Total capital (to risk-weighted assets), Required for capital1 adequacy purposes with capital buffer, Amount	$ 423,339	$ 412,718
Total capital (to risk-weighted assets), Required for capital1 adequacy purposes with capital buffer, Ratio	10.50%	10.50%
Total capital (to risk-weighted assets), For well capitalized purpose, Amount	$ 403,180	$ 393,065
Total capital (to risk-weighted assets), For well capitalized purpose, Ratio	10.00%	10.00%
Tier 1 capital (to average assets), Actual, Amount	$ 476,526	$ 479,506
Tier 1 capital (to average assets), Actual, Ratio	11.82%	12.20%
Tier 1 capital (to average assets), For capital adequacy purposes, Amount	$ 241,891	$ 235,823
Tier 1 capital (to average assets), For capital adequacy purpose, Ratio	6.00%	6.00%
Tier 1 capital (to average assets), Required for capital1 adequacy purposes with capital buffer, Amount	$ 342,679	$ 334,082
Tier 1 capital (to average assets), Required for capital1 adequacy purposes with capital buffer, Ratio	8.50%	8.50%
Tier 1 capital (to average assets), For well capitalized purpose, Amount	$ 322,522	$ 314,430
Tier 1 capital (to average assets), For well capitalized purposes, Ratio	8.00%	8.00%
Common equity tier 1 capital, Actual Amount	$ 476,526	$ 479,506
Common equity tier 1 capital, Actual Ratio	11.82%	12.20%
Common equity tier 1 capital,For capital adequacy purposes, Amount	$ 181,419	$ 176,867
Common equity tier 1 capital, For capital adequacy purpose, Ratio	4.50%	4.50%
Common equity tier 1 capital (to risk-weighted assets), Required for capital1 adequacy purposes with capital buffer, Amount	$ 282,207	$ 275,126
Common equity tier 1 capital (to risk-weighted assets), Required for capital1 adequacy purposes with capital buffer, Ratio	7.00%	7.00%
Common equity tier 1 capital, For well capitalized purpose, Amount	$ 262,049	$ 255,475
Common equity tier 1 capital, For well capitalized purposes, Ratio	6.50%	6.50%
Tier 1 capital (to average assets), Actual, Amount	$ 476,526	$ 479,506
Tier 1 capital (to average assets), Actual, Ratio	9.43%	9.49%
Tier 1 capital (to average assets), For capital adequacy purposes, Amount	$ 202,132	$ 202,110
Tier 1 capital (to average assets), For capital adequacy purpose, Ratio	4.00%	4.00%
Tier 1 capital (to average assets), Required for capital1 adequacy purposes with capital buffer, Amount	$ 202,132	$ 202,110
Tier 1 capital (to average assets), Required for capital1 adequacy purposes with capital buffer, Ratio	4.00%	4.00%
Tier 1 capital (to average assets), For well capitalized purpose, Amount	$ 252,665	$ 252,638
Tier 1 capital (to average assets), For well capitalized purposes, Ratio	5.00%	5.00%