Allowance for Loan and Lease Losses (Allocation of Allowance for Loan and Lease Losses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	$ 1,266,395	$ 1,693,372
Allowance for loan and lease losses	218,795	206,216	$ 204,466	$ 233,394
Non-PCI Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	150,189	167,966
ALLL for loans and leases individually evaluated for impairment	9,210	7,200
Impaired Financing Receivable, with Related Allowance, Recorded Investment	79,491	66,861
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	56,908	83,506
Financing Receivable, Individually Evaluated for Impairment	136,399	150,367
Average balance	135,982	136,404	127,421
Interest income recognized	4,466	4,675	5,427
Allowance for loan and lease losses	205,026	189,904	182,837	179,874
Non-PCI Loans | Commercial | Other commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	1,880	863
ALLL for loans and leases individually evaluated for impairment	152	289
Impaired Financing Receivable, with Related Allowance, Recorded Investment	1,279	305
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	284	122
Financing Receivable, Individually Evaluated for Impairment	1,563	427
Average balance	1,112	481	2,125
Interest income recognized	38	12	80
Allowance for loan and lease losses	3,269	2,168	732	1,009
Non-PCI Loans | Commercial | Construction and land development
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	1,172	4,428
ALLL for loans and leases individually evaluated for impairment	151	123
Impaired Financing Receivable, with Related Allowance, Recorded Investment	1,002	1,623
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	43	1,471
Financing Receivable, Individually Evaluated for Impairment	1,045	3,094
Average balance	2,700	3,164	1,689
Interest income recognized	138	146	83
Allowance for loan and lease losses	28,877	16,288	11,961	10,335
Non-PCI Loans | Commercial | Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	82,658	103,763
ALLL for loans and leases individually evaluated for impairment	3,488	3,370
Impaired Financing Receivable, with Related Allowance, Recorded Investment	42,875	41,793
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	33,486	53,314
Financing Receivable, Individually Evaluated for Impairment	76,361	95,107
Average balance	82,146	89,934	86,250
Interest income recognized	2,671	3,129	3,698
Allowance for loan and lease losses	48,278	69,896	85,189	100,257
Non-PCI Loans | Commercial | Commercial and industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	16,637	21,455
ALLL for loans and leases individually evaluated for impairment	1,732	1,118
Impaired Financing Receivable, with Related Allowance, Recorded Investment	8,920	8,544
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	3,680	9,366
Financing Receivable, Individually Evaluated for Impairment	12,600	17,910
Average balance	11,878	14,587	13,433
Interest income recognized	417	510	580
Allowance for loan and lease losses	50,225	43,116	30,727	22,362
Non-PCI Loans | Commercial | Lease financing
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	1,074	1,956
ALLL for loans and leases individually evaluated for impairment	75	213
Impaired Financing Receivable, with Related Allowance, Recorded Investment	1,002	1,651
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	72	104
Financing Receivable, Individually Evaluated for Impairment	1,074	1,755
Average balance	1,307	1,718	774
Interest income recognized	63	74	44
Allowance for loan and lease losses	5,907	5,524	4,286	4,749
Non-PCI Loans | Commercial | Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	233	1,260
ALLL for loans and leases individually evaluated for impairment	23	0
Impaired Financing Receivable, with Related Allowance, Recorded Investment	142	0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	0	1,183
Financing Receivable, Individually Evaluated for Impairment	142	1,183
Average balance	687	1,673	528
Interest income recognized	33	37	29
Allowance for loan and lease losses	3,127	1,855	3,184	190
Non-PCI Loans | Noncommercial | Construction and land development
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	3,030	784
ALLL for loans and leases individually evaluated for impairment	109	49
Impaired Financing Receivable, with Related Allowance, Recorded Investment	645	693
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	1,968	91
Financing Receivable, Individually Evaluated for Impairment	2,613	784
Average balance	983	829	1,678
Interest income recognized	50	38	98
Allowance for loan and lease losses	1,596	1,485	892	681
Non-PCI Loans | Noncommercial | Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	32,588	25,043
ALLL for loans and leases individually evaluated for impairment	2,447	1,212
Impaired Financing Receivable, with Related Allowance, Recorded Investment	20,269	10,097
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	11,207	12,889
Financing Receivable, Individually Evaluated for Impairment	31,476	22,986
Average balance	26,774	18,524	15,487
Interest income recognized	805	557	593
Allowance for loan and lease losses	23,094	14,105	10,661	10,511
Non-PCI Loans | Noncommercial | Revolving mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	8,831	7,120
ALLL for loans and leases individually evaluated for impairment	366	299
Impaired Financing Receivable, with Related Allowance, Recorded Investment	1,825	1,105
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	5,788	4,778
Financing Receivable, Individually Evaluated for Impairment	7,613	5,883
Average balance	6,915	4,368	3,922
Interest income recognized	171	97	134
Allowance for loan and lease losses	12,366	15,971	18,650	16,239
Non-PCI Loans | Noncommercial | Consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	2,086	1,294
ALLL for loans and leases individually evaluated for impairment	667	527
Impaired Financing Receivable, with Related Allowance, Recorded Investment	1,532	1,050
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	380	188
Financing Receivable, Individually Evaluated for Impairment	1,912	1,238
Average balance	1,480	1,126	1,535
Interest income recognized	80	75	88
Allowance for loan and lease losses	28,287	19,496	16,555	13,541
PCI Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans which have adverse change in expected cash flows	359,699	469,252
Allowance for loan and lease losses	13,769	16,312	21,629	53,520
PCI Loans | Commercial | Other commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	502	773	75	1,354
PCI Loans | Commercial | Construction and land development
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	483	1,082	150	1,320
PCI Loans | Commercial | Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	6,423	7,838	10,135	29,906
PCI Loans | Commercial | Commercial and industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	504	445	1,240	5,275
PCI Loans | Noncommercial | Construction and land development
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	0	0	183	682
PCI Loans | Noncommercial | Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	4,818	5,398	5,820	11,802
PCI Loans | Noncommercial | Revolving mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	$ 956	$ 523	$ 3,999	$ 2,959