Loans (Allowance for Loan Losses by Portfolio Class) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	$ 181,179	$ 128,762
Allowance for loan losses: Net provision for loan losses	110,659	73,038	$ 33,840
Allowance for loan losses: Increase (decrease) in FDIC loss share receivable	(3,957)	(2,800)
Allowance for loan losses: Ending balance	229,418	181,179	128,762
Allowance for loan losses: Individually evaluated for impairment	29,295	20,988
Allowance for loan losses: Amounts related to purchased credit impaired loans	18,353	23,120
Allowance for loan losses: Collectively evaluated for impairment	181,770	137,071
Loans: Individually evaluated for impairment	301,345	113,426
Loans: Purchased credit impaired loans	190,915	225,838	313,685
Loans: Collectively evaluated for impairment	16,259,891	15,364,050
Loans: Total loans	16,752,151	15,703,314
Total Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans: Total loans	12,545,507	11,560,325
Total Commercial [Member] | Commercial Real Estate - Income Producing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	6,041	7,546
Allowance for loan losses: Ending balance	13,509	6,041	7,546
Allowance for loan losses: Individually evaluated for impairment	466	1,382
Allowance for loan losses: Amounts related to purchased credit impaired loans	253	714
Allowance for loan losses: Collectively evaluated for impairment	12,790	3,945
Loans: Individually evaluated for impairment	15,376	11,122
Loans: Purchased credit impaired loans	7,928	9,193
Loans: Collectively evaluated for impairment	1,990,586	1,532,767
Loans: Total loans	2,013,890	1,553,082
Total Commercial [Member] | Construction and Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	5,642	6,421
Allowance for loan losses: Ending balance	6,271	5,642	6,421
Allowance for loan losses: Individually evaluated for impairment	38	392
Allowance for loan losses: Amounts related to purchased credit impaired loans	406	657
Allowance for loan losses: Collectively evaluated for impairment	5,827	4,593
Loans: Individually evaluated for impairment	1,938	14,226
Loans: Purchased credit impaired loans	5,271	12,103
Loans: Collectively evaluated for impairment	1,003,670	1,125,621
Loans: Total loans	1,010,879	1,151,950
Residential Mortgages [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	25,353	28,660
Allowance for loan losses: Ending balance	25,361	25,353	28,660
Allowance for loan losses: Individually evaluated for impairment	91	127
Allowance for loan losses: Amounts related to purchased credit impaired loans	15,043	17,663
Allowance for loan losses: Collectively evaluated for impairment	10,227	7,563
Loans: Individually evaluated for impairment	4,347	895
Loans: Purchased credit impaired loans	141,992	162,268
Loans: Collectively evaluated for impairment	2,000,374	1,886,361
Loans: Total loans	2,146,713	2,049,524
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	24,857	21,430
Allowance for loan losses: Ending balance	26,142	24,857	21,430
Allowance for loan losses: Individually evaluated for impairment	267	33
Allowance for loan losses: Amounts related to purchased credit impaired loans	1,271	2,547
Allowance for loan losses: Collectively evaluated for impairment	24,604	22,277
Loans: Individually evaluated for impairment	2,154	152
Loans: Purchased credit impaired loans	11,033	12,839
Loans: Collectively evaluated for impairment	2,046,744	2,080,474
Loans: Total loans	2,059,931	2,093,465
Purchased Credit Impaired [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(378)	(5,495)
Allowance for loan losses: Recoveries	972	3,886
Allowance for loan losses: Net provision for loan losses	(1,404)	(3,055)
Allowance for loan losses: Increase (decrease) in FDIC loss share receivable	(3,957)	(2,800)
Purchased Credit Impaired [Member] | Total Commercial [Member] | Commercial Real Estate - Income Producing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(1)	(2,353)
Allowance for loan losses: Recoveries	2	21
Allowance for loan losses: Net provision for loan losses	(462)	822
Allowance for loan losses: Increase (decrease) in FDIC loss share receivable		919
Purchased Credit Impaired [Member] | Total Commercial [Member] | Construction and Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(18)	(410)
Allowance for loan losses: Recoveries	361	910
Allowance for loan losses: Net provision for loan losses	(594)	(845)
Allowance for loan losses: Increase (decrease) in FDIC loss share receivable		(6)
Purchased Credit Impaired [Member] | Residential Mortgages [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(323)	(772)
Allowance for loan losses: Recoveries	36	84
Allowance for loan losses: Net provision for loan losses	1,876	1,147
Allowance for loan losses: Increase (decrease) in FDIC loss share receivable	(4,209)	(3,405)
Purchased Credit Impaired [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(8)	(143)
Allowance for loan losses: Recoveries	189	196
Allowance for loan losses: Net provision for loan losses	(1,740)	(1,313)
Allowance for loan losses: Increase (decrease) in FDIC loss share receivable	283	(188)
Non-Purchased Credit Impaired [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(72,888)	(29,163)
Allowance for loan losses: Recoveries	13,831	12,951
Allowance for loan losses: Net provision for loan losses	112,063	76,093
Non-Purchased Credit Impaired [Member] | Total Commercial [Member] | Commercial Real Estate - Income Producing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(346)	(480)
Allowance for loan losses: Recoveries	989	742
Allowance for loan losses: Net provision for loan losses	7,286	(1,176)
Non-Purchased Credit Impaired [Member] | Total Commercial [Member] | Construction and Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(964)	(2,424)
Allowance for loan losses: Recoveries	1,725	2,179
Allowance for loan losses: Net provision for loan losses	119	(183)
Non-Purchased Credit Impaired [Member] | Residential Mortgages [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(1,040)	(1,635)
Allowance for loan losses: Recoveries	859	687
Allowance for loan losses: Net provision for loan losses	2,809	587
Non-Purchased Credit Impaired [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(26,099)	(16,688)
Allowance for loan losses: Recoveries	5,809	4,338
Allowance for loan losses: Net provision for loan losses	22,851	17,225
Total Commercial & Industrial [Member] | Total Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	119,286	64,705
Allowance for loan losses: Ending balance	158,135	119,286	64,705
Allowance for loan losses: Individually evaluated for impairment	28,433	19,054
Allowance for loan losses: Amounts related to purchased credit impaired loans	1,380	1,539
Allowance for loan losses: Collectively evaluated for impairment	128,322	98,693
Loans: Individually evaluated for impairment	277,530	87,031
Loans: Purchased credit impaired loans	24,691	29,435
Loans: Collectively evaluated for impairment	9,218,517	8,738,827
Loans: Total loans	9,520,738	8,855,293
Total Commercial & Industrial [Member] | Total Commercial [Member] | Commercial Non-Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	109,428	51,169
Allowance for loan losses: Ending balance	147,052	109,428	51,169
Allowance for loan losses: Individually evaluated for impairment	28,187	19,031
Allowance for loan losses: Amounts related to purchased credit impaired loans	486	446
Allowance for loan losses: Collectively evaluated for impairment	118,379	89,951
Loans: Individually evaluated for impairment	271,262	81,622
Loans: Purchased credit impaired loans	11,368	12,004
Loans: Collectively evaluated for impairment	7,331,287	6,902,198
Loans: Total loans	7,613,917	6,995,824
Total Commercial & Industrial [Member] | Total Commercial [Member] | Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	9,858	13,536
Allowance for loan losses: Ending balance	11,083	9,858	$ 13,536
Allowance for loan losses: Individually evaluated for impairment	246	23
Allowance for loan losses: Amounts related to purchased credit impaired loans	894	1,093
Allowance for loan losses: Collectively evaluated for impairment	9,943	8,742
Loans: Individually evaluated for impairment	6,268	5,409
Loans: Purchased credit impaired loans	13,323	17,431
Loans: Collectively evaluated for impairment	1,887,230	1,836,629
Loans: Total loans	1,906,821	1,859,469
Total Commercial & Industrial [Member] | Purchased Credit Impaired [Member] | Total Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(28)	(1,817)
Allowance for loan losses: Recoveries	384	2,675
Allowance for loan losses: Net provision for loan losses	(484)	(2,866)
Allowance for loan losses: Increase (decrease) in FDIC loss share receivable	(31)	(120)
Total Commercial & Industrial [Member] | Purchased Credit Impaired [Member] | Total Commercial [Member] | Commercial Non-Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs		(1,427)
Allowance for loan losses: Recoveries	115	1,704
Allowance for loan losses: Net provision for loan losses	(44)	(1,018)
Allowance for loan losses: Increase (decrease) in FDIC loss share receivable	(31)	276
Total Commercial & Industrial [Member] | Purchased Credit Impaired [Member] | Total Commercial [Member] | Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(28)	(390)
Allowance for loan losses: Recoveries	269	971
Allowance for loan losses: Net provision for loan losses	(440)	(1,848)
Allowance for loan losses: Increase (decrease) in FDIC loss share receivable		(396)
Total Commercial & Industrial [Member] | Non-Purchased Credit Impaired [Member] | Total Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(44,439)	(7,936)
Allowance for loan losses: Recoveries	4,449	5,005
Allowance for loan losses: Net provision for loan losses	78,998	59,640
Total Commercial & Industrial [Member] | Non-Purchased Credit Impaired [Member] | Total Commercial [Member] | Commercial Non-Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(42,620)	(6,934)
Allowance for loan losses: Recoveries	3,969	3,342
Allowance for loan losses: Net provision for loan losses	76,235	62,316
Total Commercial & Industrial [Member] | Non-Purchased Credit Impaired [Member] | Total Commercial [Member] | Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(1,819)	(1,002)
Allowance for loan losses: Recoveries	480	1,663
Allowance for loan losses: Net provision for loan losses	$ 2,763	$ (2,676)