Business Combinations (Details) $ in Thousands			3 Months Ended
	Jan. 04, 2016 USD ($)	Dec. 01, 2015 USD ($) Branch	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Goodwill			$ 689,589	$ 686,339
Masters Coverage Corp.
Business Acquisition [Line Items]
Purchase price	$ 1,400
Goodwill	701
Other intangible assets acquired	$ 660
CNL Bancshares, Inc.
Business Acquisition [Line Items]
Purchase price		$ 230,000
Assets acquired		1,600,000
Loans acquired		825,000
Deposits acquired		$ 1,200,000
Number of branches acquired (in branch) | Branch		16
Common stock issued per share held (in shares)		0.705
Consideration given in stock		$ 20,600
Increase in goodwill			$ 2,500