Loans and Leases (Details 7) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period			$ 157,238
Balance, end of period	$ 159,606		159,606
The ending balance of the loan and lease portfolio is composed of loans and leases:
Ending balance of loans and leases	15,690,517		15,690,517		$ 15,455,954
Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	138,879	$ 132,000	143,755	$ 105,534
Charge-offs	(5,928)	(9,924)	(49,807)	(17,009)
Recoveries	4,865	6,050	9,608	8,811
Provision	14,954	8,621	49,214	39,411
Balance, end of period	152,770	136,747	152,770	136,747
Amount of the allowance applicable to loans and leases:
impairment	16,182	31,120	16,182	31,120
impairment	136,588	105,627	136,588	105,627
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	213,252	240,772	213,252	240,772
impairment	15,414,771	14,381,875	15,414,771	14,381,875
Ending balance of loans and leases	15,628,023	14,622,647	15,628,023	14,622,647	15,347,530
Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period			13,483
Balance, beginning of period	7,079	11,289	13,483	9,577
Charge-offs	(79)	(531)	(5,768)	(862)
Recoveries	217	0	275	0
Provision	(381)	471	(1,154)	2,514
Balance, end of period	6,836		6,836
Balance, end of period	6,836	11,229	6,836	11,229
Amount of the allowance applicable to loans and leases:
deteriorated credit quality	6,836	11,229	6,836	11,229
The ending balance of the loan and lease portfolio is composed of loans and leases:
deteriorated credit quality	62,494	120,199	62,494	120,199
Ending balance of loans and leases	62,494	120,199	62,494	120,199	108,424
NonPCI and PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	145,958	143,289	157,238	115,111
Charge-offs	(6,007)	(10,455)	(55,575)	(17,871)
Recoveries	5,082	6,050	9,883	8,811
Provision	14,573	9,092	48,060	41,925
Balance, end of period	159,606	147,976	159,606	147,976
The ending balance of the loan and lease portfolio is composed of loans and leases:
Total loans and leases	15,690,517	14,742,846	15,690,517	14,742,846
Real Estate Mortgage | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	37,122	29,331	37,765	36,654
Charge-offs	(531)	(302)	(2,217)	(1,905)
Recoveries	36	2,414	286	4,352
Provision	(186)	5,498	607	(2,160)
Balance, end of period	36,441	36,941	36,441	36,941
Amount of the allowance applicable to loans and leases:
impairment	1,153	7,299	1,153	7,299
impairment	35,288	29,642	35,288	29,642
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	113,304	139,059	113,304	139,059
impairment	6,017,892	5,325,882	6,017,892	5,325,882
Ending balance of loans and leases	6,131,196	5,464,941	6,131,196	5,464,941	5,617,956
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	7,853	10,045	7,137
Charge-offs	0	0	0	0
Recoveries	353	27	370	185
Provision	22	803	1,278	1,361
Balance, end of period	11,693	8,683	11,693	8,683
Amount of the allowance applicable to loans and leases:
impairment	0	11	0	11
impairment	11,693	8,672	11,693	8,672
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	5,764	8,700	5,764	8,700
impairment	1,243,458	822,815	1,243,458	822,815
Ending balance of loans and leases	1,249,222	831,515	1,249,222	831,515	962,839
Commercial | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	88,364	93,404	93,853	61,082
Charge-offs	(4,984)	(9,606)	(46,965)	(14,306)
Recoveries	4,447	3,553	8,848	4,179
Provision	14,366	2,240	46,457	38,636
Balance, end of period	102,193	89,591	102,193	89,591
Amount of the allowance applicable to loans and leases:
impairment	15,012	23,631	15,012	23,631
impairment	87,181	65,960	87,181	65,960
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	94,078	92,637	94,078	92,637
impairment	7,767,614	7,977,050	7,767,614	7,977,050
Ending balance of loans and leases	7,861,692	8,069,687	7,861,692	8,069,687	8,391,560
Consumer | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	2,075	1,412	2,092	661
Charge-offs	(413)	(16)	(625)	(798)
Recoveries	29	56	104	95
Provision	752	80	872	1,574
Balance, end of period	2,443	1,532	2,443	1,532
Amount of the allowance applicable to loans and leases:
impairment	17	179	17	179
impairment	2,426	1,353	2,426	1,353
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	106	376	106	376
impairment	385,807	256,128	385,807	256,128
Ending balance of loans and leases	$ 385,913	$ 256,504	$ 385,913	$ 256,504	$ 375,175