Loans and Leases (Details 1) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Allowance	$ 103,271		$ 103,271			$ 84,455
Allowance for loan and lease losses	103,271	$ 81,899	103,271	$ 81,899	$ 99,375	84,455	$ 82,149	$ 82,034
Allowance for Loan and Lease Losses, Write-offs	(5,431)	(7,956)	(16,544)	(14,940)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	1,081	1,725	5,714	3,707
Provision for Loan and Lease Losses	8,246	5,981	29,646	11,098
Loans held for investment, net	12,452,205		12,452,205			11,882,432
Loans and Leases Receivable Net Of Deferred Income Covered And Noncovered	12,452,205	11,574,885	12,452,205	11,574,885
Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Allowance	34,299	27,003	34,299	27,003
Real Estate Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Allowance	4,391	5,917	4,391	5,917
Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Allowance	52,872	29,007	52,872	29,007
Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Allowance	754	1,157	754	1,157
Purchased Credit Impaired Loans and Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Allowance	10,955		10,955			13,999
Loans and Leases Receivable, Allowance, Covered	10,955	18,815	10,955	18,815	14,328	13,999	16,626	21,793
Allowance for Loan and Lease Losses, Write-offs	(1,119)	(108)	(1,698)	(4,712)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	0	0	112	51
Provision for Loan and Lease Losses	(2,254)	2,297	(1,458)	1,683
Financing Receivable, Allowance for Credit Losses, Acquired with Deteriorated Credit Quality	10,955	18,815	10,955	18,815
Receivables Acquired with Deteriorated Credit Quality	193,289	351,379	193,289	351,379
Loans held for investment, net	193,289	351,379	193,289	351,379		290,791
NonCovered [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Allowance	92,316	63,084	92,316	63,084	85,047	70,456	65,523	60,241
Impaired Financing Receivable, Related Allowance	11,975		11,975			10,774
Allowance for Loan and Lease Losses, Write-offs	(4,312)	(7,848)	(14,846)	(10,228)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	1,081	1,725	5,602	3,656
Provision for Loan and Lease Losses	10,500	3,684	31,104	9,415
Financing Receivable, Individually Evaluated for Impairment	11,975	9,375	11,975	9,375
Financing Receivable, Collectively Evaluated for Impairment	80,341	53,709	80,341	53,709
Financing Receivable, Individually Evaluated for Impairment	146,068	120,253	146,068	120,253
Financing Receivable, Collectively Evaluated for Impairment	12,112,848	11,103,253	12,112,848	11,103,253
Loans held for investment, net	12,258,916	11,223,506	12,258,916	11,223,506		11,591,641
NonCovered [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Allowance					29,908	25,097	22,276	26,078
Impaired Financing Receivable, Related Allowance	1,443		1,443			693
Allowance for Loan and Lease Losses, Write-offs	(252)	(395)	(1,767)	(976)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	288	1,312	1,783	1,949
Provision for Loan and Lease Losses	4,355	3,810	9,186	(48)
Financing Receivable, Individually Evaluated for Impairment	1,443	1,568	1,443	1,568
Financing Receivable, Collectively Evaluated for Impairment	32,856	25,435	32,856	25,435
Financing Receivable, Individually Evaluated for Impairment	58,393	58,041	58,393	58,041
Financing Receivable, Collectively Evaluated for Impairment	5,446,694	5,340,203	5,446,694	5,340,203
Loans held for investment, net	5,505,087	5,398,244	5,505,087	5,398,244		5,340,560
NonCovered [Member] | Real Estate Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Allowance					3,908	4,248	4,302	4,298
Impaired Financing Receivable, Related Allowance	31		31			69
Allowance for Loan and Lease Losses, Write-offs	0	0	0	0
Allowance for Loan and Lease Loss, Recovery of Bad Debts	390	24	1,034	112
Provision for Loan and Lease Losses	93	1,591	(891)	1,507
Financing Receivable, Individually Evaluated for Impairment	31	119	31	119
Financing Receivable, Collectively Evaluated for Impairment	4,360	5,798	4,360	5,798
Financing Receivable, Individually Evaluated for Impairment	8,047	12,621	8,047	12,621
Financing Receivable, Collectively Evaluated for Impairment	364,433	270,446	364,433	270,446
Loans held for investment, net	372,480	283,067	372,480	283,067		307,135
NonCovered [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Allowance					50,531	39,858	35,530	26,921
Impaired Financing Receivable, Related Allowance	10,343		10,343			9,975
Allowance for Loan and Lease Losses, Write-offs	(4,035)	(7,282)	(12,964)	(9,049)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	239	337	2,393	1,301
Provision for Loan and Lease Losses	6,137	422	23,585	9,834
Financing Receivable, Individually Evaluated for Impairment	10,343	7,654	10,343	7,654
Financing Receivable, Collectively Evaluated for Impairment	42,529	21,353	42,529	21,353
Financing Receivable, Individually Evaluated for Impairment	76,088	46,143	76,088	46,143
Financing Receivable, Collectively Evaluated for Impairment	6,175,440	5,387,644	6,175,440	5,387,644
Loans held for investment, net	6,251,528	5,433,787	6,251,528	5,433,787		5,842,463
NonCovered [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Allowance					$ 700	1,253	$ 3,415	$ 2,944
Impaired Financing Receivable, Related Allowance	158		158			37
Allowance for Loan and Lease Losses, Write-offs	(25)	(171)	(115)	(203)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	164	52	392	294
Provision for Loan and Lease Losses	(85)	(2,139)	(776)	(1,878)
Financing Receivable, Individually Evaluated for Impairment	158	34	158	34
Financing Receivable, Collectively Evaluated for Impairment	596	1,123	596	1,123
Financing Receivable, Individually Evaluated for Impairment	3,540	3,448	3,540	3,448
Financing Receivable, Collectively Evaluated for Impairment	126,281	104,960	126,281	104,960
Loans held for investment, net	$ 129,821	$ 108,408	$ 129,821	$ 108,408		$ 101,483