Fair Value Measurements - Fair Value Measurement on Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Fair value measurements of assets on a recurring basis
Investment securities available for sale	$ 790,594	$ 794,645
Recurring
Fair value measurements of assets on a recurring basis
Total investment securities available for sale	790,594	794,645
Derivative assets - interest rate swaps	3,055	2,804
Derivative liabilities - interest rate swaps	3,055	2,804
Recurring \| U.S. Treasury and U.S. Government-sponsored agencies
Fair value measurements of assets on a recurring basis
Investment securities available for sale	9,448	1,569
Recurring \| Municipal securities
Fair value measurements of assets on a recurring basis
Investment securities available for sale	244,330	237,256
Recurring \| Residential
Fair value measurements of assets on a recurring basis
Investment securities available for sale	281,836	309,176
Recurring \| Commercial
Fair value measurements of assets on a recurring basis
Investment securities available for sale	208,659	208,318
Recurring \| Collateralized loan obligations
Fair value measurements of assets on a recurring basis
Investment securities available for sale	6,795	10,478
Recurring \| Corporate obligations
Fair value measurements of assets on a recurring basis
Investment securities available for sale	13,765	16,706
Recurring \| Other securities
Fair value measurements of assets on a recurring basis
Investment securities available for sale	25,761	11,142
Recurring \| Level 1
Fair value measurements of assets on a recurring basis
Total investment securities available for sale	128	123
Derivative assets - interest rate swaps	0	0
Derivative liabilities - interest rate swaps	0	0
Recurring \| Level 1 \| U.S. Treasury and U.S. Government-sponsored agencies
Fair value measurements of assets on a recurring basis
Investment securities available for sale	0	0
Recurring \| Level 1 \| Municipal securities
Fair value measurements of assets on a recurring basis
Investment securities available for sale	0	0
Recurring \| Level 1 \| Residential
Fair value measurements of assets on a recurring basis
Investment securities available for sale	0	0
Recurring \| Level 1 \| Commercial
Fair value measurements of assets on a recurring basis
Investment securities available for sale	0	0
Recurring \| Level 1 \| Collateralized loan obligations
Fair value measurements of assets on a recurring basis
Investment securities available for sale	0	0
Recurring \| Level 1 \| Corporate obligations
Fair value measurements of assets on a recurring basis
Investment securities available for sale	0	0
Recurring \| Level 1 \| Other securities
Fair value measurements of assets on a recurring basis
Investment securities available for sale	128	123
Recurring \| Level 2
Fair value measurements of assets on a recurring basis
Total investment securities available for sale	790,466	794,522
Derivative assets - interest rate swaps	3,055	2,804
Derivative liabilities - interest rate swaps	3,055	2,804
Recurring \| Level 2 \| U.S. Treasury and U.S. Government-sponsored agencies
Fair value measurements of assets on a recurring basis
Investment securities available for sale	9,448	1,569
Recurring \| Level 2 \| Municipal securities
Fair value measurements of assets on a recurring basis
Investment securities available for sale	244,330	237,256
Recurring \| Level 2 \| Residential
Fair value measurements of assets on a recurring basis
Investment securities available for sale	281,836	309,176
Recurring \| Level 2 \| Commercial
Fair value measurements of assets on a recurring basis
Investment securities available for sale	208,659	208,318
Recurring \| Level 2 \| Collateralized loan obligations
Fair value measurements of assets on a recurring basis
Investment securities available for sale	6,795	10,478
Recurring \| Level 2 \| Corporate obligations
Fair value measurements of assets on a recurring basis
Investment securities available for sale	13,765	16,706
Recurring \| Level 2 \| Other securities
Fair value measurements of assets on a recurring basis
Investment securities available for sale	25,633	11,019
Recurring \| Level 3
Fair value measurements of assets on a recurring basis
Total investment securities available for sale	0	0
Derivative assets - interest rate swaps	0	0
Derivative liabilities - interest rate swaps	0	0
Recurring \| Level 3 \| U.S. Treasury and U.S. Government-sponsored agencies
Fair value measurements of assets on a recurring basis
Investment securities available for sale	0	0
Recurring \| Level 3 \| Municipal securities
Fair value measurements of assets on a recurring basis
Investment securities available for sale	0	0
Recurring \| Level 3 \| Residential
Fair value measurements of assets on a recurring basis
Investment securities available for sale	0	0
Recurring \| Level 3 \| Commercial
Fair value measurements of assets on a recurring basis
Investment securities available for sale	0	0
Recurring \| Level 3 \| Collateralized loan obligations
Fair value measurements of assets on a recurring basis
Investment securities available for sale	0	0
Recurring \| Level 3 \| Corporate obligations
Fair value measurements of assets on a recurring basis
Investment securities available for sale	0	0
Recurring \| Level 3 \| Other securities
Fair value measurements of assets on a recurring basis
Investment securities available for sale	$ 0	$ 0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
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Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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