Loans and Leases (Details 7) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	$ 139,456
Charge-offs	(12,153)
Recoveries	7,198
Provision	(226)
Balance, end of period	134,275
Amount of the allowance applicable to loans and leases:
impairment	14,245
impairment	120,030
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	162,818
impairment	16,292,467
Ending balance of loans and leases	16,455,285		$ 16,972,743
Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	133,012	$ 143,755
Charge-offs		(20,928)
Recoveries		2,739
Provision		24,260
Balance, end of period		149,826
Amount of the allowance applicable to loans and leases:
impairment		13,427
impairment		136,399
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		228,460
impairment		15,231,894
Ending balance of loans and leases		15,460,354	16,914,707	[1],[2],[3]
Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	6,444
Balance, beginning of period		13,483
Charge-offs		(2,230)
Recoveries		0
Provision		228
Balance, end of period		11,481
Amount of the allowance applicable to loans and leases:
deteriorated credit quality		11,481
The ending balance of the loan and lease portfolio is composed of loans and leases:
deteriorated credit quality		96,335
Ending balance of loans and leases		96,335	58,036
NonPCI and PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		157,238
Charge-offs		(23,158)
Recoveries		2,739
Provision		24,488
Balance, end of period		161,307
The ending balance of the loan and lease portfolio is composed of loans and leases:
Total loans and leases		15,556,689
Real Estate Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	40,051
Charge-offs	(2,598)
Recoveries	1,657
Provision	1,048
Balance, end of period	40,158
Amount of the allowance applicable to loans and leases:
impairment	1,088
impairment	39,070
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	74,390
impairment	7,479,853
Ending balance of loans and leases	7,554,243
Real Estate Mortgage | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		37,765
Charge-offs		(1,544)
Recoveries		230
Provision		(1,083)
Balance, end of period		35,368
Amount of the allowance applicable to loans and leases:
impairment		1,070
impairment		34,298
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		118,275
impairment		5,768,694
Ending balance of loans and leases		5,886,969	7,798,991	[1],[2]
Real Estate Construction and Land
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	13,055
Charge-offs	0
Recoveries	9
Provision	5,126
Balance, end of period	18,190
Amount of the allowance applicable to loans and leases:
impairment	0
impairment	18,190
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	5,670
impairment	1,671,332
Ending balance of loans and leases	1,677,002
Real Estate Construction and Land | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		10,045
Charge-offs		0
Recoveries		8
Provision		423
Balance, end of period		10,476
Amount of the allowance applicable to loans and leases:
impairment		0
impairment		10,476
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		6,683
impairment		1,101,553
Ending balance of loans and leases		1,108,236	1,591,229	[1],[2]
Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	84,022
Charge-offs	(9,524)
Recoveries	5,487
Provision	(6,205)
Balance, end of period	73,780
Amount of the allowance applicable to loans and leases:
impairment	13,141
impairment	60,639
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	82,434
impairment	6,743,689
Ending balance of loans and leases	6,826,123
Commercial | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		93,853
Charge-offs		(19,285)
Recoveries		2,448
Provision		25,118
Balance, end of period		102,134
Amount of the allowance applicable to loans and leases:
impairment		12,267
impairment		89,867
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		103,221
impairment		7,979,457
Ending balance of loans and leases		8,082,678	7,114,920	[1],[2]
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	2,328
Charge-offs	(31)
Recoveries	45
Provision	(195)
Balance, end of period	2,147
Amount of the allowance applicable to loans and leases:
impairment	16
impairment	2,131
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	324
impairment	397,593
Ending balance of loans and leases	$ 397,917
Consumer | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		2,092
Charge-offs		(99)
Recoveries		53
Provision		(198)
Balance, end of period		1,848
Amount of the allowance applicable to loans and leases:
impairment		90
impairment		1,758
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		281
impairment		382,190
Ending balance of loans and leases		$ 382,471	$ 409,567	[1],[2]

[1] Excludes loans held for sale carried at lower of cost or fair value and PCI loans.

[2] Excludes loans held for sale carried at lower of cost or fair value and PCI loans.

[3] Excludes loans held for sale carried at lower of cost or fair value and PCI loans.