Loans and Leases (Details 7) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, beginning balance	[1],[2]	$ 139,456
Allowance for Loan and Lease Losses, Write-offs		(59,042)
Allowance for Loan and Lease Loss, Recovery of Bad Debts		15,284
Allowance for Loan and Lease Losses Write-offs, Net		(43,758)	$ (68,748)
Provision for Loan and Lease Losses		36,774
Loans and Leases Receivable, Allowance, ending balance		132,472	139,456	[1],[2]
Financing Receivable, Individually Evaluated for Impairment		4,031
Financing Receivable, Collectively Evaluated for Impairment		128,441
Financing Receivable, Individually Evaluated for Impairment		92,067
Financing Receivable, Collectively Evaluated for Impairment		17,865,646
Loans held for investment, net		17,957,713	16,972,743
Non Purchased Credit Impaired Loans and Leases [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, beginning balance		133,012	143,755
Allowance for Loan and Lease Losses, Write-offs			(74,142)
Allowance for Loan and Lease Loss, Recovery of Bad Debts			11,185
Allowance for Loan and Lease Losses Write-offs, Net			(62,957)
Provision for Loan and Lease Losses			52,214
Loans and Leases Receivable, Allowance, ending balance			133,012
Financing Receivable, Individually Evaluated for Impairment			13,621
Financing Receivable, Collectively Evaluated for Impairment			119,391
Financing Receivable, Individually Evaluated for Impairment			210,735
Financing Receivable, Collectively Evaluated for Impairment			16,703,972
Loans held for investment, net	[3],[4]		16,914,707
Purchased Credit Impaired Loans and Leases [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, beginning balance		6,444
Loans and Leases Receivable, Allowance, Covered, beginning balance		6,444	13,483
Allowance for Loan and Lease Losses, Write-offs			(6,154)
Allowance for Loan and Lease Loss, Recovery of Bad Debts			363
Allowance for Loan and Lease Losses Write-offs, Net			(5,791)
Provision for Loan and Lease Losses			(1,248)
Loans and Leases Receivable, Allowance, ending balance			6,444
Loans and Leases Receivable, Allowance, Covered, ending balance			6,444
Receivables Acquired With Deteriorated Credit Quality, Allowance For Credit Losses			6,444
Receivables Acquired with Deteriorated Credit Quality			58,036
Loans held for investment, net			58,036
NonPCI and PCI Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable Allowance Covered And Noncovered, beginning balance		139,456	157,238
Allowance for Loan and Lease Losses, Write-offs			(80,296)
Allowance for Loan and Lease Loss, Recovery of Bad Debts			11,548
Provision for Loan and Lease Losses			50,966
Loans and Leases Receivable Allowance Covered And Noncovered, ending balance			139,456
Loans and Leases Receivable Net Of Deferred Income Covered And Noncovered			16,972,743
Mortgages [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, beginning balance	[1]	40,051
Allowance for Loan and Lease Losses, Write-offs		(8,190)
Allowance for Loan and Lease Loss, Recovery of Bad Debts		2,350
Allowance for Loan and Lease Losses Write-offs, Net		(5,840)	(1,201)
Provision for Loan and Lease Losses		11,810
Loans and Leases Receivable, Allowance, ending balance		46,021	40,051	[1]
Financing Receivable, Individually Evaluated for Impairment		417
Financing Receivable, Collectively Evaluated for Impairment		45,604
Financing Receivable, Individually Evaluated for Impairment		26,473
Financing Receivable, Collectively Evaluated for Impairment		7,891,668
Loans held for investment, net		7,918,141	7,798,991	[5]
Mortgages [Member] | Non Purchased Credit Impaired Loans and Leases [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, beginning balance		34,981	37,765
Allowance for Loan and Lease Losses, Write-offs			(2,410)
Allowance for Loan and Lease Loss, Recovery of Bad Debts			1,209
Provision for Loan and Lease Losses			(1,583)
Loans and Leases Receivable, Allowance, ending balance			34,981
Financing Receivable, Individually Evaluated for Impairment			970
Financing Receivable, Collectively Evaluated for Impairment			34,011
Financing Receivable, Individually Evaluated for Impairment			115,319
Financing Receivable, Collectively Evaluated for Impairment			7,683,672
Loans held for investment, net	[3],[4]		7,798,991
Real Estate Construction [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, beginning balance	[1]	13,055
Allowance for Loan and Lease Losses, Write-offs		0
Allowance for Loan and Lease Loss, Recovery of Bad Debts		195
Allowance for Loan and Lease Losses Write-offs, Net		195	429
Provision for Loan and Lease Losses		14,959
Loans and Leases Receivable, Allowance, ending balance		28,209	13,055	[1]
Financing Receivable, Individually Evaluated for Impairment		0
Financing Receivable, Collectively Evaluated for Impairment		28,209
Financing Receivable, Individually Evaluated for Impairment		5,862
Financing Receivable, Collectively Evaluated for Impairment		2,227,794
Loans held for investment, net		2,233,656	1,591,229	[5]
Real Estate Construction [Member] | Non Purchased Credit Impaired Loans and Leases [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, beginning balance		13,055	10,045
Allowance for Loan and Lease Losses, Write-offs			0
Allowance for Loan and Lease Loss, Recovery of Bad Debts			429
Provision for Loan and Lease Losses			2,581
Loans and Leases Receivable, Allowance, ending balance			13,055
Financing Receivable, Individually Evaluated for Impairment			0
Financing Receivable, Collectively Evaluated for Impairment			13,055
Financing Receivable, Individually Evaluated for Impairment			5,690
Financing Receivable, Collectively Evaluated for Impairment			1,585,539
Loans held for investment, net	[3],[4]		1,591,229
Commercial Portfolio Segment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, beginning balance	[1]	84,022
Allowance for Loan and Lease Losses, Write-offs		(50,481)
Allowance for Loan and Lease Loss, Recovery of Bad Debts		12,566
Allowance for Loan and Lease Losses Write-offs, Net		(37,915)	(61,294)
Provision for Loan and Lease Losses		10,253
Loans and Leases Receivable, Allowance, ending balance		56,360	84,022	[1]
Financing Receivable, Individually Evaluated for Impairment		3,614
Financing Receivable, Collectively Evaluated for Impairment		52,746
Financing Receivable, Individually Evaluated for Impairment		59,288
Financing Receivable, Collectively Evaluated for Impairment		7,345,307
Loans held for investment, net		7,404,595	7,114,920	[5]
Commercial Portfolio Segment [Member] | Non Purchased Credit Impaired Loans and Leases [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, beginning balance		82,726	93,853
Allowance for Loan and Lease Losses, Write-offs			(70,709)
Allowance for Loan and Lease Loss, Recovery of Bad Debts			9,415
Provision for Loan and Lease Losses			50,167
Loans and Leases Receivable, Allowance, ending balance			82,726
Financing Receivable, Individually Evaluated for Impairment			12,635
Financing Receivable, Collectively Evaluated for Impairment			70,091
Financing Receivable, Individually Evaluated for Impairment			89,626
Financing Receivable, Collectively Evaluated for Impairment			7,025,294
Loans held for investment, net	[3],[4]		7,114,920
Consumer Portfolio Segment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, beginning balance	[1]	2,328
Allowance for Loan and Lease Losses, Write-offs		(371)
Allowance for Loan and Lease Loss, Recovery of Bad Debts		173
Allowance for Loan and Lease Losses Write-offs, Net		(198)	(891)
Provision for Loan and Lease Losses		(248)
Loans and Leases Receivable, Allowance, ending balance		1,882	2,328	[1]
Financing Receivable, Individually Evaluated for Impairment		0
Financing Receivable, Collectively Evaluated for Impairment		1,882
Financing Receivable, Individually Evaluated for Impairment		444
Financing Receivable, Collectively Evaluated for Impairment		400,877
Loans held for investment, net		401,321	409,567	[5]
Consumer Portfolio Segment [Member] | Non Purchased Credit Impaired Loans and Leases [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, beginning balance		$ 2,250	2,092
Allowance for Loan and Lease Losses, Write-offs			(1,023)
Allowance for Loan and Lease Loss, Recovery of Bad Debts			132
Provision for Loan and Lease Losses			1,049
Loans and Leases Receivable, Allowance, ending balance			2,250
Financing Receivable, Individually Evaluated for Impairment			16
Financing Receivable, Collectively Evaluated for Impairment			2,234
Financing Receivable, Individually Evaluated for Impairment			100
Financing Receivable, Collectively Evaluated for Impairment			409,467
Loans held for investment, net	[3],[4]		409,567
Purchased Credit Impaired Loans and Leases [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for Loan and Lease Losses Write-offs, Net			$ (5,791)

[1] The allowance for loan losses related to PCI loans of $6.4 million as of December 31, 2017 is reflected in the beginning balance of the allowance for loan and lease losses for the year ended December 31, 2018.

[2] The allowance for loan losses related to PCI loans of $6.4 million as of December 31, 2017 is reflected in the beginning balance of the allowance for loan and lease losses for the year ended December 31, 2018.

[3] Excludes PCI loans.

[4] {F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOjUwNzc4YjE4OWFlZTQ1MWU5MzcxMGY5M2EwOWY4MDVifFRleHRTZWxlY3Rpb246MkY4OUNBOTc0OUY1M0QwNEMyMUYwN0U5Q0Y0MTQ1MzMM}

[5] Excludes PCI loans.