Loans and Leases (Details 7) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	$ 132,139		$ 139,456
Charge-offs	(3,308)		(33,696)
Recoveries	1,589		9,886
Allowance for Loan and Lease Losses, Net charge-offs	(1,719)	$ (925)	(23,810)	$ (45,692)
Provision	11,500		26,274
Balance, end of period	141,920		141,920
Amount of the allowance applicable to loans and leases:
impairment	20,859		20,859
impairment	121,061		121,061
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	130,011		130,011
impairment	17,100,135		17,100,135
Ending balance of loans and leases	17,230,146		17,230,146		$ 16,972,743
Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		138,879	133,012	143,755
Charge-offs		(5,928)		(49,807)
Recoveries		4,865		9,608
Allowance for Loan and Lease Losses, Net charge-offs		(1,063)		(40,199)
Provision		14,954		49,214
Balance, end of period	152,770	152,770	152,770	152,770
Amount of the allowance applicable to loans and leases:
impairment		16,182		16,182
impairment		136,588		136,588
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		213,252		213,252
impairment		15,414,771		15,414,771
Ending balance of loans and leases		15,628,023		15,628,023	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		7,079		13,483
Charge-offs		(79)		(5,768)
Recoveries		217		275
Allowance for Loan and Lease Losses, Net charge-offs		138		(5,493)
Provision		(381)		(1,154)
Balance, end of period	6,836	6,836	6,836	6,836
Amount of the allowance applicable to loans and leases:
deteriorated credit quality		6,836		6,836
The ending balance of the loan and lease portfolio is composed of loans and leases:
deteriorated credit quality		62,494		62,494
Ending balance of loans and leases		62,494		62,494	58,036
NonPCI and PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		145,958		157,238
Charge-offs		(6,007)		(55,575)
Recoveries		5,082		9,883
Provision		14,573		48,060
Balance, end of period	159,606	159,606	159,606	159,606
The ending balance of the loan and lease portfolio is composed of loans and leases:
Total loans and leases		15,690,517		15,690,517
Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for Loan and Lease Losses, Net charge-offs		138		(5,493)
Real Estate Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	45,467		40,051
Charge-offs	(726)		(8,071)
Recoveries	222		1,999
Allowance for Loan and Lease Losses, Net charge-offs	(504)	(495)	(6,072)	(1,931)
Provision	1,394		12,378
Balance, end of period	46,357		46,357
Amount of the allowance applicable to loans and leases:
impairment	496		496
impairment	45,861		45,861
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	44,985		44,985
impairment	7,633,675		7,633,675
Ending balance of loans and leases	7,678,660		7,678,660
Real Estate Mortgage | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		37,122		37,765
Charge-offs		(531)		(2,217)
Recoveries		36		286
Provision		(186)		607
Balance, end of period	36,441	36,441	36,441	36,441
Amount of the allowance applicable to loans and leases:
impairment		1,153		1,153
impairment		35,288		35,288
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		113,304		113,304
impairment		6,017,892		6,017,892
Ending balance of loans and leases		6,131,196		6,131,196	7,798,991	[2],[3]
Real Estate Construction and Land
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	26,210		13,055
Charge-offs	0		0
Recoveries	23		49
Allowance for Loan and Lease Losses, Net charge-offs	23	353	49	370
Provision	(47)		13,082
Balance, end of period	26,186		26,186
Amount of the allowance applicable to loans and leases:
impairment	0		0
impairment	26,186		26,186
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	5,533		5,533
impairment	1,995,424		1,995,424
Ending balance of loans and leases	2,000,957		2,000,957
Real Estate Construction and Land | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		11,318		10,045
Charge-offs		0		0
Recoveries		353		370
Provision		22		1,278
Balance, end of period	11,693	11,693	11,693	11,693
Amount of the allowance applicable to loans and leases:
impairment		0		0
impairment		11,693		11,693
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		5,764		5,764
impairment		1,243,458		1,243,458
Ending balance of loans and leases		1,249,222		1,249,222	1,591,229	[2],[3]
Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	58,806		84,022
Charge-offs	(2,372)		(25,321)
Recoveries	1,303		7,702
Allowance for Loan and Lease Losses, Net charge-offs	(1,069)	(537)	(17,619)	(38,117)
Provision	9,907		1,241
Balance, end of period	67,644		67,644
Amount of the allowance applicable to loans and leases:
impairment	20,363		20,363
impairment	47,281		47,281
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	79,493		79,493
impairment	7,072,565		7,072,565
Ending balance of loans and leases	7,152,058		7,152,058
Commercial | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		88,364		93,853
Charge-offs		(4,984)		(46,965)
Recoveries		4,447		8,848
Provision		14,366		46,457
Balance, end of period	102,193	102,193	102,193	102,193
Amount of the allowance applicable to loans and leases:
impairment		15,012		15,012
impairment		87,181		87,181
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		94,078		94,078
impairment		7,767,614		7,767,614
Ending balance of loans and leases		7,861,692		7,861,692	7,114,920	[2],[3]
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	1,656		2,328
Charge-offs	(210)		(304)
Recoveries	41		136
Allowance for Loan and Lease Losses, Net charge-offs	(169)	(384)	(168)	(521)
Provision	246		(427)
Balance, end of period	1,733		1,733
Amount of the allowance applicable to loans and leases:
impairment	0		0
impairment	1,733		1,733
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	0		0
impairment	398,471		398,471
Ending balance of loans and leases	398,471		398,471
Consumer | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		2,075		2,092
Charge-offs		(413)		(625)
Recoveries		29		104
Provision		752		872
Balance, end of period	$ 2,443	2,443	$ 2,443	2,443
Amount of the allowance applicable to loans and leases:
impairment		17		17
impairment		2,426		2,426
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		106		106
impairment		385,807		385,807
Ending balance of loans and leases		385,913		385,913	$ 409,567	[2],[3]
Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for Loan and Lease Losses, Net charge-offs		$ (1,063)		$ (40,199)

[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.