Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]
Net interest income	$ 51,491	$ 39,880	$ 150,902	$ 117,471
Provision for loan and lease losses	2,553	5,149	11,635	7,648
Total noninterest income	20,162	20,379	59,626	69,604
Total noninterest expense	54,211	46,808	160,487	140,220
INCOME BEFORE INCOME TAXES	14,889	8,302	38,406	39,207
Segment Assets	5,934,809	4,912,730	5,934,809	4,912,730	5,923,716
Average Loans	3,812,218	2,937,508	3,692,718	2,906,970
Community and Other Banking
Segment Reporting Information [Line Items]
Net interest income	50,790	39,292	148,930	115,968
Provision for loan and lease losses	2,553	5,149	11,635	7,648
Total noninterest income	11,124	11,971	33,720	35,190
Total noninterest expense	42,784	35,511	127,743	104,199
INCOME BEFORE INCOME TAXES	16,577	10,603	43,272	39,311
Segment Assets	5,817,427	4,825,781	5,817,427	4,825,781
Average Loans	3,736,917	2,867,933	3,629,822	2,820,418
Retail Mortgage Banking
Segment Reporting Information [Line Items]
Net interest income	701	588	1,972	1,503
Provision for loan and lease losses	0	0	0	0
Total noninterest income	9,038	8,408	25,906	34,414
Total noninterest expense	11,427	11,297	32,744	36,021
INCOME BEFORE INCOME TAXES	(1,688)	(2,301)	(4,866)	(104)
Segment Assets	117,382	86,949	117,382	86,949
Average Loans	$ 75,301	$ 69,575	$ 62,896	$ 86,552