Loans and Leases (Allowance For Loan And Lease Losses By Portfolio Segment) (Detail) - USD ($) $ in Thousands	3 Months Ended										12 Months Ended
	Dec. 31, 2015		Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014		Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period					$ 159,264					$ 152,573	$ 159,264		$ 152,573		$ 177,129
Provision (benefit) charged to expense	$ 13,800		$ 13,000	$ 12,750	9,750	$ 9,500		$ 9,500	$ 9,250	9,000	49,300		37,250		33,500
Losses charged off											(43,560)		(44,426)		(75,459)
Recoveries											9,986		13,867		17,403
Balance, end of period	174,990					159,264					174,990		159,264		152,573
Individually evaluated for impairment	22,204					25,301					22,204		25,301		20,453
Collectively evaluated for impairment	152,786					133,963					152,786		133,963		132,120
Individually evaluated for impairment	279,171					330,856					279,171		330,856		351,541
Collectively evaluated for impairment	15,392,564					13,569,169					15,392,564		13,569,169		12,348,235
Total Loans and Leases	15,671,735	[1],[2]				13,900,025	[1],[2]				15,671,735	[1],[2]	13,900,025	[1],[2]	12,699,776
Residential Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period					25,452					23,027	25,452		23,027		32,030
Provision (benefit) charged to expense											6,057		7,315		1,187
Losses charged off											(6,508)		(6,214)		(11,592)
Recoveries											875		1,324		1,402
Balance, end of period	25,876					25,452					25,876		25,452		23,027
Individually evaluated for impairment	10,364					12,094					10,364		12,094		10,535
Collectively evaluated for impairment	15,512					13,358					15,512		13,358		12,492
Individually evaluated for impairment	134,448					141,982					134,448		141,982		142,413
Collectively evaluated for impairment	3,926,553					3,367,193					3,926,553		3,367,193		3,219,012
Total Loans and Leases	4,061,001					3,509,175	[3]				4,061,001		3,509,175	[3]	3,361,425
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period					43,518					41,951	43,518		41,951		56,995
Provision (benefit) charged to expense											11,847		17,224		7,808
Losses charged off											(17,679)		(20,712)		(29,037)
Recoveries											4,366		5,055		6,185
Balance, end of period	42,052					43,518					42,052		43,518		41,951
Individually evaluated for impairment	3,477					4,237					3,477		4,237		4,595
Collectively evaluated for impairment	38,575					39,281					38,575		39,281		37,356
Individually evaluated for impairment	48,425					50,249					48,425		50,249		52,092
Collectively evaluated for impairment	2,654,135					2,499,152					2,654,135		2,499,152		2,484,596
Total Loans and Leases	2,702,560					2,549,401					2,702,560		2,549,401		2,536,688
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period					52,114					51,001	52,114		51,001		50,562
Provision (benefit) charged to expense											23,356		10,412		14,442
Losses charged off											(11,522)		(13,668)		(19,126)
Recoveries											2,738		4,369		5,123
Balance, end of period	66,686					52,114					66,686		52,114		51,001
Individually evaluated for impairment	5,197					2,710					5,197		2,710		1,878
Collectively evaluated for impairment	61,489					49,404					61,489		49,404		49,123
Individually evaluated for impairment	56,581					36,176					56,581		36,176		52,018
Collectively evaluated for impairment	4,259,418					3,713,094					4,259,418		3,713,094		3,230,833
Total Loans and Leases	4,315,999					3,749,270					4,315,999		3,749,270		3,282,851
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period					32,102					32,408	32,102		32,408		33,210
Provision (benefit) charged to expense											9,718		2,046		12,975
Losses charged off											(7,578)		(3,237)		(15,425)
Recoveries											647		885		1,648
Balance, end of period	34,889					32,102					34,889		32,102		32,408
Individually evaluated for impairment	3,163					6,232					3,163		6,232		3,445
Collectively evaluated for impairment	31,726					25,870					31,726		25,870		28,963
Individually evaluated for impairment	39,295					101,817					39,295		101,817		104,808
Collectively evaluated for impairment	3,952,354					3,452,611					3,952,354		3,452,611		2,953,554
Total Loans and Leases	3,991,649					3,554,428					3,991,649		3,554,428		3,058,362
Finance Leases Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period					$ 6,078					$ 4,186	6,078		4,186		4,332
Provision (benefit) charged to expense											(1,678)		253		(2,912)
Losses charged off											(273)		(595)		(279)
Recoveries											1,360		2,234		3,045
Balance, end of period	5,487					6,078					5,487		6,078		4,186
Individually evaluated for impairment	3					28					3		28		0
Collectively evaluated for impairment	5,484					6,050					5,484		6,050		4,186
Individually evaluated for impairment	422					632					422		632		210
Collectively evaluated for impairment	600,104					537,119					600,104		537,119		460,240
Total Loans and Leases	$ 600,526					$ 537,751					$ 600,526		$ 537,751		$ 460,450

[1] Accrued interest of $43.1 million and $38.4 million at December 31, 2015 and December 31, 2014, respectively, are not included in the loan and lease balances.

[2] Loan and lease balances include net deferred fees and unamortized premiums of $18.0 million and $10.6 million at December 31, 2015 and December 31, 2014, respectively.

[3] U.S. Government guaranteed loans of approximately $2.0 million were reclassified from non-accrual to over 90 days past due and accruing reflective of a policy change effective in the first quarter of 2015.