Subsequent Events (Details) $ / shares in Units, $ in Thousands			3 Months Ended
	Apr. 26, 2017 USD ($) $ / shares shares	Jan. 03, 2017 USD ($) shares	Mar. 31, 2017 USD ($) location shares	Dec. 31, 2016 USD ($) shares	Mar. 31, 2016 USD ($) shares
Subsequent events
Assets			$ 11,150,070	$ 8,900,592	$ 8,670,757
Loans			7,868,840	6,643,326	6,129,228
Deposits			$ 9,033,438	$ 7,334,423	$ 7,161,948
Common Stock, Shares, Outstanding | shares			24,230,734	24,230,392	24,177,833
Share Price | $ / shares	$ 91.90
Loans		$ 1,049,950
SBFC
Subsequent events
Fixed stock exchange ratio		0.7307
Aggregate consideration		$ 435,115
Business consideration received, common stock (in shares) | shares		4,978,338
PSC
Subsequent events
Assets			$ 3,300,000
Loans			2,500,000
Deposits			$ 2,500,000
Number of full service branches | location			50
Fixed stock exchange ratio	0.14
Aggregate consideration	$ 690,800
Common Stock, Shares, Outstanding | shares	53,112,726		53,112,726