Mergers and Acquisitions - (Details Textual) $ in Thousands	Jul. 01, 2017 USD ($) shares	Apr. 01, 2016 USD ($) branch shares	Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jun. 30, 2016 USD ($) branch
Business Acquisition [Line Items]
Goodwill resulting from merger			$ 470,534	$ 470,534	$ 470,534
Metropolitan Bancgroup, Inc.
Business Acquisition [Line Items]
Assets acquired					1,220,000
Recognized identifiable assets acquired and liabilities assumed, financial assets					990,000
Deposits					$ 940,000
Number of locations acquired | branch					8
KeyWorth Bank
Business Acquisition [Line Items]
Transaction value		$ 58,884
Payment to stock option holders		$ 3,594
Voting interest acquired (percent)		100.00%
Assets acquired		$ 415,232
Recognized identifiable assets acquired and liabilities assumed, financial assets		$ 272,330
Number of offices in operation | branch		6
Intangible assets, including goodwill		$ 22,643
Goodwill resulting from merger		20,633
Core deposit intangible		$ 2,010
Weighted average useful life (in years)		10 years
KeyWorth Bank | Core Deposits
Business Acquisition [Line Items]
Deposits		$ 348,961
KeyWorth Bank | Common Stock
Business Acquisition [Line Items]
Shares issued to common shareholders (shares) | shares		1,680,021
Subsequent Event | Metropolitan Bancgroup, Inc.
Business Acquisition [Line Items]
Transaction value	$ 218,000
Shares issued to common shareholders (shares) | shares	4,883,182
Payment to stock option holders	$ 4,764
Voting interest acquired (percent)	100.00%