Segment Reporting (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Net Interest Income	$ 75,160	$ 73,681	$ 73,118	$ 72,707	$ 62,700	$ 59,724	$ 57,644	$ 53,930	$ 294,666	$ 233,998	$ 203,073
Provision for loan losses	2,181	5,328	2,118	2,067	2,171	3,181	5,674	1,671	11,694	12,697	14,501
Total noninterest income	24,455	28,542	31,026	29,578	24,381	24,980	30,661	30,663	113,601	110,685	82,224
Total noninterest expense	69,912	$ 68,427	$ 71,020	$ 70,309	65,954	$ 61,996	$ 63,482	$ 59,614	279,668	251,046	215,800
Income (loss) before income taxes									116,905	80,940	54,996
Segment Assets	8,247,079				7,694,754				8,247,079	7,694,754	6,051,812
Average Loans, Net of Unearned									5,488,112	4,551,008	3,744,830
Community and Other Banking
Segment Reporting Information [Line Items]
Net Interest Income									290,088	228,422	200,394
Provision for loan losses									11,694	12,697	14,501
Total noninterest income									74,145	65,414	48,330
Total noninterest expense									237,198	201,063	172,392
Income (loss) before income taxes									115,341	80,076	61,831
Segment Assets	8,149,465				7,585,130				8,149,465	7,585,130	5,951,325
Average Loans, Net of Unearned									5,418,169	4,466,528	3,679,908
Mortgage Banking
Segment Reporting Information [Line Items]
Net Interest Income									4,578	5,576	2,679
Provision for loan losses									0	0	0
Total noninterest income									39,456	45,271	33,894
Total noninterest expense									42,470	49,983	43,408
Income (loss) before income taxes									1,564	864	(6,835)
Segment Assets	$ 97,614				$ 109,624				97,614	109,624	100,487
Average Loans, Net of Unearned									$ 69,943	$ 84,480	$ 64,922