Regulatory Matters (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2016	Dec. 31, 2017	Dec. 31, 2016
Tier 1 Leverage
Amount available without prior regulatory approval for dividends		$ 68,300
Parent Company
Total Capital
Total Capital (to risk-weighted assets), Actual, Capital Amount		$ 355,722	$ 201,496
Total Capital (to risk weighted assets), Actual, Ratio (as a percent)		13.70%	10.60%
Total Capital, Minimum Amount Required for Adequately Capitalized, Capital Amount		$ 207,657	$ 151,459
Total Capital (to risk weighted assets), Minimum Amount Required for Adequately Capitalized, Ratio (as a percent)		8.00%	8.00%
Tier I Capital
Tier I Capital, (to risk-weighted assets), Actual, Capital Amount		$ 347,411	$ 195,188
Tier I Capital (to risk weighted assets), Actual, Ratio (as a percent)		13.40%	10.30%
Tier I Capital, Minimum Amount Required for Adequately Capitalized, Capital Amount		$ 155,743	$ 113,594
Tier I Capital (to risk weighted assets), Minimum Amount Required for Adequately Capitalized, Ratio (as a percent)		6.00%	6.00%
Common Equity Tier I Capital 1
Common Equity Tier I Capital 1, Actual, Capital Amount		$ 305,830	$ 153,607
Common Equity Tier I Capital 1 (to risk weighted assets), Ratio (as a percent)		11.80%	8.10%
Common Equity Tier I Capital 1, Minimum Amount Required for Adequately Capitalized, Capital Amount		$ 116,807	$ 85,196
Common Equity Tier I Capital 1 (to risk weighted assets, Minimum Amount Required for Adequately Capitalized, Ratio (as a percent)		4.50%	4.50%
Tier 1 Leverage
Tier 1 Leverage, Actual, Capital Amount		$ 347,411	$ 195,188
Tier 1 Leverage (to average assets), Actual, Ratio (as a percent)		10.90%	6.60%
Tier 1 Leverage, Minimum Amount Required for Adequately Capitalized, Capital Amount		$ 127,318	$ 118,082
Tier 1 Leverage (to average assets), Minimum Amount Required for Adequately Capitalized, Ratio (as a percent)		4.00%	4.00%
Federal Deposit Corporation And Federal Reserve Board | Rules Phased in beginning January 2016
Tier 1 Leverage
New capital conservation buffer requirement beginning Ratio		0.625%
Basel III Capital Rules related to CET1, period (in years)	4 years	4 years
Additional capital conservation buffer requirement subsequent years Ratio		2.50%
Bank
Total Capital
Total Capital (to risk-weighted assets), Actual, Capital Amount		$ 406,638	$ 255,539
Total Capital (to risk weighted assets), Actual, Ratio (as a percent)		15.70%	13.50%
Total Capital, Minimum Amount Required for Adequately Capitalized, Capital Amount		$ 207,567	$ 151,332
Total Capital (to risk weighted assets), Minimum Amount Required for Adequately Capitalized, Ratio (as a percent)		8.00%	8.00%
Total capital, Minimum Amount To Be Well Capitalized, Capital Amount		$ 259,459	$ 189,165
Total Capital (to risk weighted assets), Minimum Amount To Be Well Capitalized, Ratio (as a percent)		10.00%	10.00%
Tier I Capital
Tier I Capital, (to risk-weighted assets), Actual, Capital Amount		$ 398,327	$ 249,231
Tier I Capital (to risk weighted assets), Actual, Ratio (as a percent)		15.40%	13.20%
Tier I Capital, Minimum Amount Required for Adequately Capitalized, Capital Amount		$ 155,675	$ 113,499
Tier I Capital (to risk weighted assets), Minimum Amount Required for Adequately Capitalized, Ratio (as a percent)		6.00%	6.00%
Tier I Capital, Minimum Amount To Be Well Capitalized, Capital Amount		$ 207,567	$ 151,332
Tier I Capital (to risk weighted assets), Minimum Amount To Be Well Capitalized, Ratio (as a percent)		8.00%	8.00%
Common Equity Tier I Capital 1
Common Equity Tier I Capital 1, Actual, Capital Amount		$ 398,327	$ 249,231
Common Equity Tier I Capital 1 (to risk weighted assets), Ratio (as a percent)		15.40%	13.20%
Common Equity Tier I Capital 1, Minimum Amount Required for Adequately Capitalized, Capital Amount		$ 116,756	$ 85,124
Common Equity Tier I Capital 1 (to risk weighted assets, Minimum Amount Required for Adequately Capitalized, Ratio (as a percent)		4.50%	4.50%
Common Equity Tier I Capital 1, Minimum Amount To Be Well Capitalized, Capital Amount		$ 168,648	$ 122,957
Common Equity Tier I Capital 1 (to risk weighted assets), Minimum Amount To Be Well Capitalized, Ratio (as a percent)		6.50%	6.50%
Tier 1 Leverage
Tier 1 Leverage, Actual, Capital Amount		$ 398,327	$ 249,231
Tier 1 Leverage (to average assets), Actual, Ratio (as a percent)		12.50%	8.40%
Tier 1 Leverage, Minimum Amount Required for Adequately Capitalized, Capital Amount		$ 127,593	$ 118,258
Tier 1 Leverage (to average assets), Minimum Amount Required for Adequately Capitalized, Ratio (as a percent)		4.00%	4.00%
Tier 1 Leverage, Minimum Amount To Be Well Capitalized, Capital Amount		$ 159,491	$ 147,822
Tier 1 Leverage (to average assets), Minimum Amount To Be Well Capitalized, Ratio (as a percent)		5.00%	5.00%