Loans And Leases (Recorded Investment In Loans And Leases) (Detail) (USD $)	Sep. 30, 2013		Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Individually evaluated for impairment	$ 397,256,000	[1]	$ 428,121,000	[1]
Collectively evaluated for impairment	12,117,221,000	[1]	11,635,935,000	[1]
Recorded investment in loans and leases	12,514,477,000	[1]	12,064,056,000	[1]
Less: Accrued interest	36,512,000	[1]	35,360,000	[1]
Loans and leases	12,477,965,000	[1]	12,028,696,000	[1]
Unamortized premiums	13,200,000		12,700,000
Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Individually evaluated for impairment	143,534,000		146,944,000
Collectively evaluated for impairment	3,217,268,000		3,155,051,000
Recorded investment in loans and leases	3,360,802,000		3,301,995,000
Less: Accrued interest	10,225,000		10,271,000
Loans and leases	3,350,577,000		3,291,724,000
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Individually evaluated for impairment	52,907,000		54,793,000
Collectively evaluated for impairment	2,487,122,000		2,584,169,000
Recorded investment in loans and leases	2,540,029,000		2,638,962,000
Less: Accrued interest	7,730,000		8,095,000
Loans and leases	2,532,299,000		2,630,867,000
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Individually evaluated for impairment	62,190,000		69,426,000
Collectively evaluated for impairment	3,134,197,000		2,843,760,000
Recorded investment in loans and leases	3,196,387,000		2,913,186,000
Less: Accrued interest	10,988,000		9,453,000
Loans and leases	3,185,399,000		2,903,733,000
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Individually evaluated for impairment	138,333,000	[2]	154,978,000	[2]
Collectively evaluated for impairment	2,853,099,000	[2]	2,635,624,000	[2]
Recorded investment in loans and leases	2,991,432,000	[2]	2,790,602,000	[2]
Less: Accrued interest	7,569,000	[2]	7,541,000	[2]
Loans and leases	2,983,863,000	[2]	2,783,061,000	[2]
Equipment financing [Member]
Financing Receivable, Recorded Investment [Line Items]
Individually evaluated for impairment	292,000		1,980,000
Collectively evaluated for impairment	425,535,000		417,331,000
Recorded investment in loans and leases	425,827,000		419,311,000
Less: Accrued interest	0		0
Loans and leases	$ 425,827,000		$ 419,311,000

[1] Loans and leases include net deferred fees and unamortized premiums of $13.2 million and $12.7 million at September 30, 2013 and December 31, 2012, respectively.

[2] Includes certain loans individually evaluated for impairment, under the Company's loan policy, that were deemed not to be impaired at both September 30, 2013 and December 31, 2012.