Regulatory Capital - Summary of Regulatory Capital Requirement (Details) $ in Thousands	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital (to risk-weighted assets), Actual, Amount	$ 678,665	$ 648,804
Total capital (to risk-weighted assets), Actual, Ratio	0.1527	0.1491
Total capital (to risk-weighted assets), For capital adequacy purposes, Amount	$ 355,555	$ 348,024
Total capital (to risk-weighted assets), For capital adequacy purposes, Ratio	0.0800	0.0800
Total capital (to risk-weighted assets), Required for capital1 adequacy purposes with capital buffer, Amount	$ 466,666	$ 456,782
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	$ 634,105	$ 607,340
Tier 1 capital (to average assets), Actual, Ratio	0.1427	0.1396
Tier 1 capital (to average assets), For capital adequacy purposes, Amount	$ 266,617	$ 261,018
Tier 1 capital (to average assets), For capital adequacy purpose, Ratio	0.0600	0.0600
Tier 1 capital (to average assets), Required for capital1 adequacy purposes with capital buffer, Amount	$ 377,708	$ 369,775
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	$ 518,670	$ 491,281
Common equity tier 1 capital, Actual Ratio	0.1167	0.1129
Common equity tier 1 capital, For capital adequacy purposes, Amount	$ 200,001	$ 195,764
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 capital adequacy purposes with capital buffer, Amount	$ 311,113	$ 304,522
Common equity tier 1 capital (to risk-weighted assets), Required for capital adequacy purposes with capital buffer, Ratio	7.00%	7.00%
Tier 1 capital (to average assets), Actual, Amount	$ 634,105	$ 607,340
Tier 1 capital (to average assets), Actual, Ratio	0.1003	0.1068
Tier 1 capital (to average assets), For capital adequacy purposes, Amount	$ 252,883	$ 227,507
Tier 1 capital (to average assets), For capital adequacy purpose, Ratio	0.0400	0.0400
Tier 1 capital (to average assets), Required for capital1 adequacy purposes with capital buffer, Amount	$ 252,883	$ 227,507
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	$ 575,693	$ 532,315
Total capital (to risk-weighted assets), Actual, Ratio	0.1297	0.1221
Total capital (to risk-weighted assets), For capital adequacy purposes, Amount	$ 355,092	$ 348,810
Total capital (to risk-weighted assets), For capital adequacy purposes, Ratio	0.0800	0.0800
Total capital (to risk-weighted assets), Required for capital1 adequacy purposes with capital buffer, Amount	$ 466,058	$ 457,813
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	$ 443,865	$ 436,013
Total capital (to risk-weighted assets), For well capitalized purpose, Ratio	0.1000	0.1000
Tier 1 capital (to average assets), Actual, Amount	$ 526,731	$ 492,221
Tier 1 capital (to average assets), Actual, Ratio	0.1186	0.1129
Tier 1 capital (to average assets), For capital adequacy purposes, Amount	$ 266,474	$ 261,606
Tier 1 capital (to average assets), For capital adequacy purpose, Ratio	0.0600	0.0600
Tier 1 capital (to average assets), Required for capital1 adequacy purposes with capital buffer, Amount	$ 377,505	$ 370,609
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	$ 355,299	$ 348,808
Tier 1 capital (to average assets), For well capitalized purposes, Ratio	0.0800	0.0800
Common equity tier 1 capital, Actual Amount	$ 526,731	$ 492,221
Common equity tier 1 capital, Actual Ratio	0.1186	0.1129
Common equity tier 1 capital, For capital adequacy purposes, Amount	$ 199,856	$ 196,205
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 capital adequacy purposes with capital buffer, Amount	$ 310,887	$ 305,207
Common equity tier 1 capital (to risk-weighted assets), Required for capital adequacy purposes with capital buffer, Ratio	7.00%	7.00%
Common equity tier 1 capital, For well capitalized purpose, Amount	$ 288,681	$ 283,407
Common equity tier 1 capital, For well capitalized purposes, Ratio	6.50%	6.50%
Tier 1 capital (to average assets), Actual, Amount	$ 526,731	$ 492,221
Tier 1 capital (to average assets), Actual, Ratio	0.0838	0.0871
Tier 1 capital (to average assets), For capital adequacy purposes, Amount	$ 251,423	$ 226,158
Tier 1 capital (to average assets), For capital adequacy purpose, Ratio	0.0400	0.0400
Tier 1 capital (to average assets), Required for capital1 adequacy purposes with capital buffer, Amount	$ 251,423	$ 226,158
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	$ 314,279	$ 282,697
Tier 1 capital (to average assets), For well capitalized purposes, Ratio	0.0500	0.0500