Stockholders' Equity and Acquisitions - Acquisitions (Details) - USD ($) shares in Millions			1 Months Ended	12 Months Ended
	Apr. 01, 2015	May. 30, 2014	May. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Common stock issued for acquisitions				$ 0	$ 83,517,000	$ 0
Tax receivable overstated		$ 543,000
Increase (decrease) in income taxes receivable			$ (543,000)
Assets acquired:
Goodwill				$ 411,624,000	$ 392,757,000
The MDE Group [Member]
Business Acquisition [Line Items]
Goodwill acquired	$ 18,300,000
Contingent consideration liability at fair value	338,000
Payment agreement limit	12,500,000.0
Team Capital [Member]
Business Acquisition [Line Items]
Consideration transferred		115,100,000
Acquisition purchase price		31,600,000
Common stock issued for acquisitions		83,500,000
Assets acquired:
Cash and cash equivalents, net		68,650,000
Securities available for sale		157,635,000
Loans		631,209,000
Bank-owned life insurance		22,319,000
Banking premises and equipment		24,778,000
Accrued interest receivable		3,060,000
Goodwill		40,897,000
Other intangibles assets		9,868,000
Foreclosed assets, net		653,000
Other assets		4,905,000
Total assets acquired		963,974,000
Liabilities assumed:
Deposits		769,936,000
Borrowed Funds		112,835,000
Other liabilities		(2,314,000)
Total liabilities assumed		880,457,000
Net assets acquired		$ 83,517,000
Common Stock [Member] | Team Capital [Member]
Business Acquisition [Line Items]
Number of shares		4.9
Customer Relationships [Member] | The MDE Group [Member]
Business Acquisition [Line Items]
Customer relationship intangible acquired	$ 7,000,000