Loans and Leases (Details 8) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	$ 136,281	$ 134,275	$ 132,472
Charge-offs	(17,637)	(18,235)	(21,102)
Recoveries	6,393	1,099	9,667
Allowance for Loan and Lease Losses, Net charge-offs	(11,244)	(17,136)	(11,435)
Provision	10,000	15,000	14,000
Balance, end of period	135,037	132,139	135,037	$ 132,139
The ending balance of the loan and lease portfolio is composed of loans and leases:
Ending balance of loans and leases	18,472,852		18,472,852		$ 17,957,713
Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	136,281	134,275	132,472	139,456
Charge-offs	(17,637)	(18,235)	(21,102)	(30,388)
Recoveries	6,393	1,099	9,667	8,297
Allowance for Loan and Lease Losses, Net charge-offs				(22,091)
Provision	10,000	15,000	14,000	14,774
Balance, end of period	135,037	132,139	135,037	132,139
Amount of the allowance applicable to loans and leases:
Individually evaluated for impairment	4,742	8,952	4,742	8,952
Collectively evaluated for impairment	130,295	123,187	130,295	123,187
The ending balance of the loan and lease portfolio is composed of loans and leases:
Individually evaluated for impairment	93,350	167,157	93,350	167,157
Collectively evaluated for impairment	18,379,502	16,718,035	18,379,502	16,718,035
Ending balance of loans and leases	18,472,852	16,885,192	18,472,852	16,885,192	17,957,713
Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period				6,400
Real Estate Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for Loan and Lease Losses, Net charge-offs	(294)	(4,627)	(347)	(5,568)
The ending balance of the loan and lease portfolio is composed of loans and leases:
Ending balance of loans and leases	8,076,026		8,076,026		7,918,141
Real Estate Mortgage \| Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	45,754	40,158	46,021	40,051
Charge-offs	(534)	(4,747)	(730)	(7,345)
Recoveries	240	120	383	1,777
Provision	1,366	9,936	1,152	10,984
Balance, end of period	46,826	45,467	46,826	45,467
Amount of the allowance applicable to loans and leases:
Individually evaluated for impairment	260	472	260	472
Collectively evaluated for impairment	46,566	44,995	46,566	44,995
The ending balance of the loan and lease portfolio is composed of loans and leases:
Individually evaluated for impairment	27,594	83,931	27,594	83,931
Collectively evaluated for impairment	8,048,432	7,482,443	8,048,432	7,482,443
Ending balance of loans and leases	8,076,026	7,566,374	8,076,026	7,566,374	7,918,141
Real Estate Construction and Land
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for Loan and Lease Losses, Net charge-offs	0	17	0	26
The ending balance of the loan and lease portfolio is composed of loans and leases:
Ending balance of loans and leases	2,376,130		2,376,130		2,233,656
Real Estate Construction and Land \| Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	27,208	18,190	28,209	13,055
Charge-offs	0	0	0	0
Recoveries	0	17	0	26
Provision	(830)	8,003	(1,831)	13,129
Balance, end of period	26,378	26,210	26,378	26,210
Amount of the allowance applicable to loans and leases:
Individually evaluated for impairment	0	0	0	0
Collectively evaluated for impairment	26,378	26,210	26,378	26,210
The ending balance of the loan and lease portfolio is composed of loans and leases:
Individually evaluated for impairment	5,376	15,998	5,376	15,998
Collectively evaluated for impairment	2,370,754	1,858,028	2,370,754	1,858,028
Ending balance of loans and leases	2,376,130	1,874,026	2,376,130	1,874,026	2,233,656
Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for Loan and Lease Losses, Net charge-offs	(10,847)	(12,513)	(10,744)	(16,550)
The ending balance of the loan and lease portfolio is composed of loans and leases:
Ending balance of loans and leases	7,574,314		7,574,314		7,404,595
Commercial \| Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	61,496	73,780	56,360	84,022
Charge-offs	(16,927)	(13,425)	(19,930)	(22,949)
Recoveries	6,080	912	9,186	6,399
Provision	8,752	(2,461)	13,785	(8,666)
Balance, end of period	59,401	58,806	59,401	58,806
Amount of the allowance applicable to loans and leases:
Individually evaluated for impairment	4,482	8,480	4,482	8,480
Collectively evaluated for impairment	54,919	50,326	54,919	50,326
The ending balance of the loan and lease portfolio is composed of loans and leases:
Individually evaluated for impairment	60,380	67,228	60,380	67,228
Collectively evaluated for impairment	7,513,934	6,998,884	7,513,934	6,998,884
Ending balance of loans and leases	7,574,314	7,066,112	7,574,314	7,066,112	7,404,595
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for Loan and Lease Losses, Net charge-offs	(103)	(13)	(344)	1
The ending balance of the loan and lease portfolio is composed of loans and leases:
Ending balance of loans and leases					401,321
Consumer \| Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	1,823	2,147	1,882	2,328
Charge-offs	(176)	(63)	(442)	(94)
Recoveries	73	50	98	95
Provision	712	(478)	894	(673)
Balance, end of period	2,432	1,656	2,432	1,656
Amount of the allowance applicable to loans and leases:
Individually evaluated for impairment	0	0	0	0
Collectively evaluated for impairment	2,432	1,656	2,432	1,656
The ending balance of the loan and lease portfolio is composed of loans and leases:
Individually evaluated for impairment	0	0	0	0
Collectively evaluated for impairment	446,382	378,680	446,382	378,680
Ending balance of loans and leases	446,382	378,680	446,382	378,680	$ 401,321
Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for Loan and Lease Losses, Net charge-offs	$ (11,244)	$ (17,136)	$ (11,435)	$ (22,091)

Financing Receivable, Allowance for Credit Loss, Additional Information, Portfolio Composition [Abstract]

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Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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Amount, after recoveries, of loans and leases that have been written-off.

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