Loans and Allowance for Credit Losses Past Due Loan Status and Non-Accrual Loans by Portfolio Segment (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 185,275	$ 186,787
≥ 90 Days Past Due and Accruing	13,143	11,505
Non- accrual	122,600	120,133
Current	15,161,342	14,512,485
Loans, net of unearned income	15,346,617	14,699,272	$ 14,155,159
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	39,814	41,938
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	9,718	13,211
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	135,743	131,638
Real-estate - commercial mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	41,511	47,195
≥ 90 Days Past Due and Accruing	309	383
Non- accrual	32,267	38,936
Current	6,220,497	5,971,387
Loans, net of unearned income	6,262,008	6,018,582	5,635,347
Real-estate - commercial mortgage | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	8,259	6,254
Real-estate - commercial mortgage | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	676	1,622
Real-estate - commercial mortgage | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	32,576	39,319
Commercial - secured
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	59,460	51,824
≥ 90 Days Past Due and Accruing	3,135	959
Non- accrual	47,489	41,589
Current	4,043,125	3,881,728
Loans, net of unearned income	4,102,585	3,933,552
Commercial - secured | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,411	6,660
Commercial - secured | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,425	2,616
Commercial - secured | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	50,624	42,548
Commercial - unsecured
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,183	1,845
≥ 90 Days Past Due and Accruing	98	152
Non- accrual	598	760
Current	142,081	152,089
Loans, net of unearned income	143,264	153,934
Commercial - unsecured | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	430	898
Commercial - unsecured | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	57	35
Commercial - unsecured | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	696	912
Commercial - industrial, financial and agricultural
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	60,643	53,669
≥ 90 Days Past Due and Accruing	3,233	1,111
Non- accrual	48,087	42,349
Current	4,185,206	4,033,817
Loans, net of unearned income	4,245,849	4,087,486	4,099,177
Commercial - industrial, financial and agricultural | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,841	7,558
Commercial - industrial, financial and agricultural | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,482	2,651
Commercial - industrial, financial and agricultural | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	51,320	43,460
Real-estate - home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	22,110	22,428
≥ 90 Days Past Due and Accruing	2,167	2,543
Non- accrual	9,720	10,611
Current	1,557,629	1,602,687
Loans, net of unearned income	1,579,739	1,625,115	1,647,319
Real-estate - home equity | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	8,103	6,596
Real-estate - home equity | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,120	2,678
Real-estate - home equity | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	11,887	13,154
Real estate - residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	37,735	43,999
≥ 90 Days Past Due and Accruing	4,906	5,224
Non- accrual	16,940	18,431
Current	1,746,977	1,557,995
Loans, net of unearned income	1,784,712	1,601,994	1,447,292
Real estate - residential mortgage | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	12,640	15,600
Real estate - residential mortgage | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,249	4,744
Real estate - residential mortgage | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	21,846	23,655
Construction - commercial residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	15,315	8,595
≥ 90 Days Past Due and Accruing	978	36
Non- accrual	13,779	8,275
Current	141,976	133,594
Loans, net of unearned income	157,291	142,189
Construction - commercial residential | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	538	233
Construction - commercial residential | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	20	51
Construction - commercial residential | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	14,757	8,311
Construction - commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	716	1,178
≥ 90 Days Past Due and Accruing	0	0
Non- accrual	716	435
Current	727,933	643,312
Loans, net of unearned income	728,649	644,490
Construction - commercial | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	743
Construction - commercial | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Construction - commercial | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	716	435
Construction - other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,091	1,096
≥ 90 Days Past Due and Accruing	0	0
Non- accrual	1,091	1,096
Current	51,869	55,874
Loans, net of unearned income	52,960	56,970
Construction - other | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Construction - other | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Construction - other | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,091	1,096
Real-estate - construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	17,122	10,869
≥ 90 Days Past Due and Accruing	978	36
Non- accrual	15,586	9,806
Current	921,778	832,780
Loans, net of unearned income	938,900	843,649	853,699
Real-estate - construction | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	538	976
Real-estate - construction | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	20	51
Real-estate - construction | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	16,564	9,842
Consumer - direct
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,904	3,315
≥ 90 Days Past Due and Accruing	1,143	1,563
Non- accrual	0	0
Current	55,825	93,572
Loans, net of unearned income	58,729	96,887
Consumer - direct | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,054	1,211
Consumer - direct | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	707	541
Consumer - direct | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,143	1,563
Consumer - indirect
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,047	3,927
≥ 90 Days Past Due and Accruing	126	328
Non- accrual	0	0
Current	222,380	190,656
Loans, net of unearned income	224,427	194,583
Consumer - indirect | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,708	3,200
Consumer - indirect | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	213	399
Consumer - indirect | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	126	328
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,951	7,242
≥ 90 Days Past Due and Accruing	1,269	1,891
Non- accrual	0	0
Current	278,205	284,228
Loans, net of unearned income	283,156	291,470	278,071
Consumer | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,762	4,411
Consumer | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	920	940
Consumer | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,269	1,891
Leasing, other and overdrafts
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,203	1,385
≥ 90 Days Past Due and Accruing	281	317
Non- accrual	0	0
Current	251,050	229,591
Loans, net of unearned income	252,253	230,976	$ 194,254
Leasing, other and overdrafts | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	671	543
Leasing, other and overdrafts | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	251	525
Leasing, other and overdrafts | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 281	$ 317