Loans and Allowance for Loan Losses (Allowance for Loan Losses by Portfolio Class) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	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	$ 17,196	$ 6,608	77,232	12,762
Allowance for loan losses: Increase (decrease) in FDIC loss share receivable			(3,437)	(2,536)
Allowance for loan losses: Ending balance	226,086	131,087	226,086	131,087
Allowance for loan losses: Individually evaluated for impairment	13,349	5,562	13,349	5,562
Allowance for loan losses: Amounts related to purchased credit impaired loans	19,590	24,062	19,590	24,062
Allowance for loan losses: Collectively evaluated for impairment	193,147	101,463	193,147	101,463
Loans: Individually evaluated for impairment	248,967	72,607	248,967	72,607
Loans: Purchased credit impaired loans	209,924	259,437	209,924	259,437	$ 225,838	$ 313,685
Loans: Collectively evaluated for impairment	15,576,905	14,012,708	15,576,905	14,012,708
Loans: Total loans	16,035,796	14,344,752	16,035,796	14,344,752	15,703,314
Total Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans: Total loans	11,953,778		11,953,778		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	12,799	5,500	12,799	5,500
Allowance for loan losses: Individually evaluated for impairment	72	228	72	228
Allowance for loan losses: Amounts related to purchased credit impaired loans	741	973	741	973
Allowance for loan losses: Collectively evaluated for impairment	11,986	4,299	11,986	4,299
Loans: Individually evaluated for impairment	7,803	12,682	7,803	12,682
Loans: Purchased credit impaired loans	10,752	15,563	10,752	15,563
Loans: Collectively evaluated for impairment	2,005,916	1,423,846	2,005,916	1,423,846
Loans: Total loans	2,024,471	1,452,091	2,024,471	1,452,091	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	5,006	5,301	5,006	5,301
Allowance for loan losses: Individually evaluated for impairment	1	73	1	73
Allowance for loan losses: Amounts related to purchased credit impaired loans	575	390	575	390
Allowance for loan losses: Collectively evaluated for impairment	4,430	4,838	4,430	4,838
Loans: Individually evaluated for impairment	1,247	4,360	1,247	4,360
Loans: Purchased credit impaired loans	8,761	19,465	8,761	19,465
Loans: Collectively evaluated for impairment	870,580	1,097,122	870,580	1,097,122
Loans: Total loans	880,588	1,120,947	880,588	1,120,947	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	23,474	24,689	23,474	24,689
Allowance for loan losses: Individually evaluated for impairment	167	163	167	163
Allowance for loan losses: Amounts related to purchased credit impaired loans	15,430	17,419	15,430	17,419
Allowance for loan losses: Collectively evaluated for impairment	7,877	7,107	7,877	7,107
Loans: Individually evaluated for impairment	1,068	1,369	1,068	1,369
Loans: Purchased credit impaired loans	151,674	171,107	151,674	171,107
Loans: Collectively evaluated for impairment	1,864,908	1,783,361	1,864,908	1,783,361
Loans: Total loans	2,017,650	1,955,837	2,017,650	1,955,837	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	23,359	20,286	23,359	20,286
Allowance for loan losses: Individually evaluated for impairment	41	6	41	6
Allowance for loan losses: Amounts related to purchased credit impaired loans	1,257	2,998	1,257	2,998
Allowance for loan losses: Collectively evaluated for impairment	22,061	17,282	22,061	17,282
Loans: Individually evaluated for impairment	166	116	166	116
Loans: Purchased credit impaired loans	12,826	14,860	12,826	14,860
Loans: Collectively evaluated for impairment	2,051,376	1,854,475	2,051,376	1,854,475
Loans: Total loans	2,064,368	1,869,451	2,064,368	1,869,451	2,093,465
Purchased Credit Impaired [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(78)	(4,060)
Allowance for loan losses: Recoveries			292	1,023
Allowance for loan losses: Net provision for loan losses			(307)	(949)
Allowance for loan losses: Increase (decrease) in FDIC loss share receivable			(3,437)	(2,536)
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
Allowance for loan losses: Net provision for loan losses			26	1,102
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)	(285)
Allowance for loan losses: Recoveries			53	406
Allowance for loan losses: Net provision for loan losses			(117)	(733)
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			(23)	(168)
Allowance for loan losses: Recoveries			3	2
Allowance for loan losses: Net provision for loan losses			1,165	272
Allowance for loan losses: Increase (decrease) in FDIC loss share receivable			(3,378)	(3,296)
Purchased Credit Impaired [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(8)	(140)
Allowance for loan losses: Recoveries			106	136
Allowance for loan losses: Net provision for loan losses			(1,290)	(889)
Allowance for loan losses: Increase (decrease) in FDIC loss share receivable			(98)	(104)
Non-Purchased Credit Impaired [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(36,054)	(11,589)
Allowance for loan losses: Recoveries			6,952	6,725
Allowance for loan losses: Net provision for loan losses			77,539	13,711
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			(191)	(147)
Allowance for loan losses: Recoveries			268	291
Allowance for loan losses: Net provision for loan losses			6,654	(1,858)
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			(592)	(828)
Allowance for loan losses: Recoveries			1,125	1,308
Allowance for loan losses: Net provision for loan losses			(1,087)	(982)
Non-Purchased Credit Impaired [Member] | Residential Mortgages [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(592)	(1,292)
Allowance for loan losses: Recoveries			480	449
Allowance for loan losses: Net provision for loan losses			466	62
Non-Purchased Credit Impaired [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(11,268)	(6,729)
Allowance for loan losses: Recoveries			3,039	2,491
Allowance for loan losses: Net provision for loan losses			8,021	4,091
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	161,448	75,311	161,448	75,311
Allowance for loan losses: Individually evaluated for impairment	13,068	5,092	13,068	5,092
Allowance for loan losses: Amounts related to purchased credit impaired loans	1,587	2,282	1,587	2,282
Allowance for loan losses: Collectively evaluated for impairment	146,793	67,937	146,793	67,937
Loans: Individually evaluated for impairment	238,683	54,080	238,683	54,080
Loans: Purchased credit impaired loans	25,911	38,442	25,911	38,442
Loans: Collectively evaluated for impairment	8,784,125	7,853,904	8,784,125	7,853,904
Loans: Total loans	9,048,719	7,946,426	9,048,719	7,946,426	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	150,772	60,323	150,772	60,323
Allowance for loan losses: Individually evaluated for impairment	12,885	2,903	12,885	2,903
Allowance for loan losses: Amounts related to purchased credit impaired loans	572	643	572	643
Allowance for loan losses: Collectively evaluated for impairment	137,315	56,777	137,315	56,777
Loans: Individually evaluated for impairment	232,785	32,379	232,785	32,379
Loans: Purchased credit impaired loans	10,483	13,667	10,483	13,667
Loans: Collectively evaluated for impairment	6,889,251	6,139,638	6,889,251	6,139,638
Loans: Total loans	7,132,519	6,185,684	7,132,519	6,185,684	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	10,676	14,988	10,676	14,988
Allowance for loan losses: Individually evaluated for impairment	183	2,189	183	2,189
Allowance for loan losses: Amounts related to purchased credit impaired loans	1,015	1,639	1,015	1,639
Allowance for loan losses: Collectively evaluated for impairment	9,478	11,160	9,478	11,160
Loans: Individually evaluated for impairment	5,898	21,701	5,898	21,701
Loans: Purchased credit impaired loans	15,428	24,775	15,428	24,775
Loans: Collectively evaluated for impairment	1,894,874	1,714,266	1,894,874	1,714,266
Loans: Total loans	$ 1,916,200	$ 1,760,742	1,916,200	1,760,742	$ 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)	(1,114)
Allowance for loan losses: Recoveries			128	479
Allowance for loan losses: Net provision for loan losses			(91)	(701)
Allowance for loan losses: Increase (decrease) in FDIC loss share receivable			39	(49)
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				(1,099)
Allowance for loan losses: Recoveries			8	14
Allowance for loan losses: Net provision for loan losses			79	470
Allowance for loan losses: Increase (decrease) in FDIC loss share receivable			39	347
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)	(15)
Allowance for loan losses: Recoveries			120	465
Allowance for loan losses: Net provision for loan losses			(170)	(1,171)
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			(23,411)	(2,593)
Allowance for loan losses: Recoveries			2,040	2,186
Allowance for loan losses: Net provision for loan losses			63,485	12,398
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			(22,212)	(2,215)
Allowance for loan losses: Recoveries			1,802	2,051
Allowance for loan losses: Net provision for loan losses			61,628	9,586
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			(1,199)	(378)
Allowance for loan losses: Recoveries			238	135
Allowance for loan losses: Net provision for loan losses			$ 1,857	$ 2,812