Regulatory Capital Requirements (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital	$ 202,530	$ 187,790
Capital to risk weighted assets	11.87%	12.12%
Capital required for capital adequacy	$ 147,108	$ 123,979
Capital required for capital adequacy to risk weighted assets	8.625%	8.00%
Tier one risk based capital	$ 186,418	$ 172,807
Tier one risk based capital to risk weighted assets	10.93%	11.15%
Tier one risk based capital required for capital adequacy	$ 112,996	$ 92,984
Tier one risk based capital required for capital adequacy to risk weighted assets	6.625%	6.00%
Common equity tier one capital	$ 166,418	$ 152,807
Common equity tier one capital to risk weighted assets	9.76%	9.86%
Common equity tier one capital required for capital adequacy	$ 87,412	$ 69,738
Common equity tier one capital required for capital adequacy to risk weighted assets	5.125%	4.50%
Tier one leverage capital	$ 186,418	$ 172,807
Tier one leverage capital to average assets	10.14%	9.91%
Tier one leverage capital required for capital adequacy	$ 73,530	$ 69,764
Tier one leverage capital required for capital adequacy to average assets	4.00%	4.00%
Tangible capital to tangible assets	8.92%	8.71%
Intangible assets	$ 0	$ 0
West Bank [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital	$ 186,118	$ 174,450
Capital to risk weighted assets	11.04%	11.32%
Capital required for capital adequacy	$ 145,414	$ 123,279
Capital required for capital adequacy to risk weighted assets	8.625%	8.00%
Capital required to be well capitalized	$ 168,597	$ 154,099
Capital required to be well capitalized to risk weighted assets	10.00%	10.00%
Tier one risk based capital	$ 170,006	$ 159,467
Tier one risk based capital to risk weighted assets	10.08%	10.35%
Tier one risk based capital required for capital adequacy	$ 111,695	$ 92,460
Tier one risk based capital required for capital adequacy to risk weighted assets	6.625%	6.00%
Tier one risk based capital required to be well capitalized	$ 134,877	$ 123,279
Tier one risk based capital required to be well capitalized to risk weighted assets	8.00%	8.00%
Common equity tier one capital	$ 170,006	$ 159,467
Common equity tier one capital to risk weighted assets	10.08%	10.35%
Common equity tier one capital required for capital adequacy	$ 86,406	$ 69,345
Common equity tier one capital required for capital adequacy to risk weighted assets	5.125%	4.50%
Common equity tier one capital required to be well capitalized	$ 109,588	$ 100,164
Common equity tier one capital required to be well capitalized to risk weighted assets	6.50%	6.50%
Tier one leverage capital	$ 170,006	$ 159,467
Tier one leverage capital to average assets	9.34%	9.20%
Tier one leverage capital required for capital adequacy	$ 72,807	$ 69,352
Tier one leverage capital required for capital adequacy to average assets	4.00%	4.00%
Tier one leverage capital required to be well capitalized	$ 91,009	$ 86,690
Tier one leverage capital required to be well capitalized to average assets	5.00%	5.00%