Regulatory Capital Requirements (Details) - USD ($) $ in Thousands		12 Months Ended
	Oct. 08, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2008
Total risk-based capital:
Actual Regulatory Capital - Amount		$ 368,856	$ 335,740
Capital To Risk Weighted Assets		14.04%	12.98%
Minimum Requirement for capital Adequacy Including Capital Buffer Total Risk-Based Capital Ratio		8.63%
Minimum Regulatory Capital Required - Ratio		8.00%	8.00%
Tier 1 capital:
Actual Regulatory Capital - Amount		$ 330,729	$ 299,552
Actual Regulatory Capital - Ratio		12.59%	11.58%
Minimum Requirement for capital Adequacy Including Capital Buffer Tier I Risk-Based Capital Ratio		6.63%
Minimum Regulatory Capital Required - Ratio		6.00%	6.00%
Common equity tier I capital		$ 296,120	$ 269,350
Tier 1 leverage capital ratio:
Actual Regulatory Capital - Amount		$ 330,729	$ 299,552
Actual Regulatory Capital - Ratio		8.83%	8.74%
Minimum Regulatory Capital Required - Ratio		4.00%	4.00%
Common Equity Tier I Risk Based Capital Ratio		11.27%	10.42%
Minimum Requirement for capital Adequacy Including Capital Buffer Common Equity Tier I Risk-Based Capital Ratio		5.13%
Common Equity Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets		4.50%	4.50%
Capital Conservation Buffer		2.50%
Value Of Trust Preferred Securities Included In Tier One Capital		$ 43,000	$ 43,000	$ 43,000
Subordinated Debt	$ 15,000	$ 58,755	58,599
Debt Instrument, Term	10 years	10 years
Subordinated Borrowing, Interest Rate	5.50%
Subsidiaries [Member]
Total risk-based capital:
Actual Regulatory Capital - Amount		$ 340,908	$ 304,847
Capital To Risk Weighted Assets		12.92%	11.75%
Minimum Requirement for capital Adequacy Including Capital Buffer Total Risk-Based Capital Ratio		8.63%
Minimum Regulatory Capital Required - Ratio			8.00%
Minimum Regulatory Provision To Be Well Capitalized - Ratio		10.00%	10.00%
Tier 1 capital:
Actual Regulatory Capital - Amount		$ 317,782	$ 283,659
Actual Regulatory Capital - Ratio		12.05%	10.93%
Minimum Requirement for capital Adequacy Including Capital Buffer Tier I Risk-Based Capital Ratio		6.63%
Minimum Regulatory Capital Required - Ratio			6.00%
Minimum Regulatory Provision To Be Well Capitalized - Ratio		8.00%	8.00%
Common equity tier I capital		$ 317,782	$ 283,659
Tier 1 leverage capital ratio:
Actual Regulatory Capital - Amount		$ 317,782	$ 283,659
Actual Regulatory Capital - Ratio		8.54%	8.33%
Minimum Regulatory Capital Required - Ratio		4.00%	4.00%
Minimum Regulatory Provision To Be Well Capitalized - Ratio		5.00%	5.00%
Common Equity Tier I Risk Based Capital Ratio		12.05%	10.93%
Minimum Requirement for capital Adequacy Including Capital Buffer Common Equity Tier I Risk-Based Capital Ratio		5.13%
Common Equity Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets			4.50%
Common Equity Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets		6.50%	6.50%
Tier II Capital [Domain]
Tier 1 leverage capital ratio:
Subordinated Debt		$ 15,000	$ 15,000
Minimum [Member]
Tier 1 leverage capital ratio:
Capital Conservation Buffer		0.625%