Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015 segment	Mar. 31, 2014	Dec. 31, 2014
Segment Reporting [Abstract]
Number of operating segments	2
Segment Reporting Information [Line Items]
Net interest income	$ 53,930	$ 48,612
Provision for loan losses	1,671	6,331
Total noninterest income	30,663	18,850
Total noninterest expense	59,614	52,538
INCOME BEFORE INCOME TAXES	23,308	8,593
Average Loans, for the period	4,267,593	3,571,127
Segment Assets, at period end	6,506,276	5,746,892	6,051,812
Community and Other Banking
Segment Reporting Information [Line Items]
Net interest income	52,889	47,855
Provision for loan losses	1,671	6,331
Total noninterest income	17,061	11,526
Total noninterest expense	47,459	42,337
INCOME BEFORE INCOME TAXES	20,820	10,713
Average Loans, for the period	4,189,966	3,528,356
Segment Assets, at period end	6,365,682	5,669,302
Retail Mortgage Banking
Segment Reporting Information [Line Items]
Net interest income	1,041	757
Provision for loan losses	0	0
Total noninterest income	13,602	7,324
Total noninterest expense	12,155	10,201
INCOME BEFORE INCOME TAXES	2,488	(2,120)
Average Loans, for the period	77,627	42,771
Segment Assets, at period end	$ 140,594	$ 77,590