Capital Requirements (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Bank [Member]
Capital Requirements [Line Items]
Actual total capital, amount	$ 243,301	$ 124,149
Actual total capital, ratio	11.66%	10.58%
Minimum capital requirement, amount	$ 182,517	$ 93,866
Minimum capital requirement, ratio	8.75%	8.625%
Minimum to be well capitalized under prompt corrective action provisions, amount	$ 208,591	$ 117,332
Minimum to be well capitalized under prompt corrective action provisions, ratio	10.00%	10.00%
Tier One Risk Based Capital [Abstract]
Actual, amount	$ 225,743	$ 109,457
Actual, ratio	10.82%	9.33%
Minimum capital requirement, amount	$ 140,799	$ 70,399
Minimum capital requirement, ratio	6.75%	6.625%
Minimum to be well capitalized under prompt corrective action provisions, amount	$ 166,873	$ 93,866
Minimum to be well capitalized under prompt corrective action provisions, ratio	8.00%	8.00%
Tier One Leverage Capital [Abstract]
Actual, amount	$ 225,743	$ 109,457
Actual, ratio	8.51%	8.11%
Minimum capital requirement, amount	$ 139,313	$ 60,793
Minimum capital requirement, ratio	5.25%	5.125%
Minimum to be well capitalized under prompt correction action provisions, amount	$ 132,679	$ 67,547
Minimum to be well capitalized under prompt correction action provisions, ratio	5.00%	5.00%
Common Equity Tier One Capital [Abstract]
Actual, amount	$ 225,743	$ 109,457
Actual, ratio	10.82%	9.33%
Minimum capital requirement, amount	$ 83,436	$ 46,933
Minimum capital requirement, ratio	4.00%	4.00%
Minimum to be well capitalized under prompt corrective action provisions, amount	$ 135,584	$ 76,266
Minimum to be well capitalized under prompt corrective action provisions, ratio	6.50%	6.50%
Corporation [Member]
Capital Requirements [Line Items]
Actual total capital, amount	$ 257,139	$ 135,009
Actual total capital, ratio	12.25%	11.51%
Minimum capital requirement, amount	$ 183,670	$ 93,866
Minimum capital requirement, ratio	8.75%	8.625%
Minimum to be well capitalized under prompt corrective action provisions, amount	$ 209,909	$ 117,333
Minimum to be well capitalized under prompt corrective action provisions, ratio	10.00%	10.00%
Tier One Risk Based Capital [Abstract]
Actual, amount	$ 240,535	$ 120,317
Actual, ratio	11.46%	10.25%
Minimum capital requirement, amount	$ 141,689	$ 70,400
Minimum capital requirement, ratio	6.75%	6.625%
Minimum to be well capitalized under prompt corrective action provisions, amount	$ 167,927	$ 93,866
Minimum to be well capitalized under prompt corrective action provisions, ratio	8.00%	8.00%
Tier One Leverage Capital [Abstract]
Actual, amount	$ 240,535	$ 120,317
Actual, ratio	8.48%	8.90%
Minimum capital requirement, amount	$ 148,986	$ 52,800
Minimum capital requirement, ratio	5.25%	5.125%
Minimum to be well capitalized under prompt correction action provisions, amount	$ 141,892	$ 58,667
Minimum to be well capitalized under prompt correction action provisions, ratio	5.00%	5.00%
Common Equity Tier One Capital [Abstract]
Actual, amount	$ 240,535	$ 120,317
Actual, ratio	11.46%	10.25%
Minimum capital requirement, amount	$ 83,964	$ 54,068
Minimum capital requirement, ratio	4.00%	4.00%
Minimum to be well capitalized under prompt corrective action provisions, amount	$ 136,441	$ 87,861
Minimum to be well capitalized under prompt corrective action provisions, ratio	6.50%	6.50%