Segment Reporting (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) segment	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment	2
Segment Reporting Information [Line Items]
Net interest income	$ 72,707	$ 53,930
Provision for loan losses	2,067	1,671
Total noninterest income	29,578	30,663
Total noninterest expense	70,309	59,614
INCOME BEFORE INCOME TAXES	29,909	23,308
Average Loans, for the period	5,358,102	4,267,593
Segment Assets, at period end	8,253,779	6,506,276	$ 7,694,754
Operating Segments | Community and Other Banking
Segment Reporting Information [Line Items]
Net interest income	71,583	52,889
Provision for loan losses	2,067	1,671
Total noninterest income	18,537	17,061
Total noninterest expense	59,739	47,459
INCOME BEFORE INCOME TAXES	28,314	20,820
Average Loans, for the period	5,296,191	4,189,966
Segment Assets, at period end	8,141,960	6,365,682
Operating Segments | Retail Mortgage Banking
Segment Reporting Information [Line Items]
Net interest income	1,124	1,041
Provision for loan losses	0	0
Total noninterest income	11,041	13,602
Total noninterest expense	10,570	12,155
INCOME BEFORE INCOME TAXES	1,595	2,488
Average Loans, for the period	61,911	77,627
Segment Assets, at period end	$ 111,819	$ 140,594