Fair Value Measurements (Summary Of Estimated Fair Values Of Significant Financial Instruments) (Detail) (USD $)	Dec. 31, 2013		Dec. 31, 2012
Fair Value Measurements [Line Items]
Securities available for sale and held-to-maturity	$ 2,754,856,000		$ 685,797,000
Mortgage servicing assets, reserves	200,000		1,800,000
Hedge accounting adjustments and discounts	61,000		85,000
Hedge Accounting Adjustments And Discounts - Long Term Debt	1,000,000		4,400,000
Alternative Investments [Member]
Fair Value Measurements [Line Items]
Other assets	600,000
Fair Value, Measurements, Recurring [Member]
Fair Value Measurements [Line Items]
Securities available for sale and held-to-maturity	3,106,931,000		3,136,160,000
Derivative instruments - assets	42,303,000		53,867,000
Securities sold under agreements to repurchase and other borrowings	1,331,662,000		1,076,160,000
Federal Home Loan Bank advances	2,052,421,000	[1]	1,827,612,000	[1]
Long-term debt	228,365,000		334,276,000	[2]
Derivative instruments - liabilities	24,006,000		43,301,000
Fair Value, Measurements, Recurring [Member] | Deposits other than time deposits [Member]
Fair Value Measurements [Line Items]
Deposits	12,627,276,000		11,985,683,000
Fair Value, Measurements, Recurring [Member] | Time deposits [Member]
Fair Value Measurements [Line Items]
Deposits	2,227,144,000		2,545,152,000
Fair Value, Measurements, Recurring [Member] | Securities available for sale [Member]
Fair Value Measurements [Line Items]
Securities available for sale and held-to-maturity	3,106,931,000		3,136,160,000
Fair Value, Measurements, Recurring [Member] | Securities held to maturity [Member]
Fair Value Measurements [Line Items]
Securities available for sale and held-to-maturity	3,358,721,000		3,107,529,000
Fair Value, Measurements, Recurring [Member] | Alternative Investments [Member]
Fair Value Measurements [Line Items]
Other assets	16,582,000		15,340,000
Fair Value, Measurements, Recurring [Member] | Investments held in Rabbi Trust [Member]
Fair Value Measurements [Line Items]
Other assets	6,097,000		5,741,000
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value Measurements [Line Items]
Securities available for sale and held-to-maturity	3,634,000		8,282,000
Derivative instruments - assets	0		0
Securities sold under agreements to repurchase and other borrowings	0		0
Federal Home Loan Bank advances	0	[1]	0	[1]
Long-term debt	0		0	[2]
Derivative instruments - liabilities	227,000		125,000
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Deposits other than time deposits [Member]
Fair Value Measurements [Line Items]
Deposits	0		0
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Time deposits [Member]
Fair Value Measurements [Line Items]
Deposits	0		0
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Securities available for sale [Member]
Fair Value Measurements [Line Items]
Securities available for sale and held-to-maturity	3,634,000		8,282,000
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Securities held to maturity [Member]
Fair Value Measurements [Line Items]
Securities available for sale and held-to-maturity	0		0
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Alternative Investments [Member]
Fair Value Measurements [Line Items]
Other assets	0		0
Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Investments held in Rabbi Trust [Member]
Fair Value Measurements [Line Items]
Other assets	6,097,000		5,741,000
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Measurements [Line Items]
Securities available for sale and held-to-maturity	3,074,807,000		3,013,131,000
Derivative instruments - assets	42,303,000		53,867,000
Securities sold under agreements to repurchase and other borrowings	1,365,427,000		1,134,614,000
Federal Home Loan Bank advances	2,063,612,000	[1]	1,843,615,000	[1]
Long-term debt	221,613,000		298,807,000	[2]
Derivative instruments - liabilities	23,779,000		43,176,000
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Deposits other than time deposits [Member]
Fair Value Measurements [Line Items]
Deposits	12,627,276,000		11,985,683,000
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Time deposits [Member]
Fair Value Measurements [Line Items]
Deposits	2,250,141,000		2,584,921,000
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Securities available for sale [Member]
Fair Value Measurements [Line Items]
Securities available for sale and held-to-maturity	3,074,807,000		3,013,131,000
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Securities held to maturity [Member]
Fair Value Measurements [Line Items]
Securities available for sale and held-to-maturity	3,370,912,000		3,264,718,000
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Alternative Investments [Member]
Fair Value Measurements [Line Items]
Other assets	0		0
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Investments held in Rabbi Trust [Member]
Fair Value Measurements [Line Items]
Other assets
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurements [Line Items]
Securities available for sale and held-to-maturity	28,490,000		114,747,000
Derivative instruments - assets	0		0
Securities sold under agreements to repurchase and other borrowings	0		0
Federal Home Loan Bank advances	0	[1]	0	[1]
Long-term debt	0		0	[2]
Derivative instruments - liabilities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Deposits other than time deposits [Member]
Fair Value Measurements [Line Items]
Deposits	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Time deposits [Member]
Fair Value Measurements [Line Items]
Deposits	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Securities available for sale [Member]
Fair Value Measurements [Line Items]
Securities available for sale and held-to-maturity	28,490,000		114,747,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Securities held to maturity [Member]
Fair Value Measurements [Line Items]
Securities available for sale and held-to-maturity	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Alternative Investments [Member]
Fair Value Measurements [Line Items]
Other assets	16,582,000		15,340,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Investments held in Rabbi Trust [Member]
Fair Value Measurements [Line Items]
Other assets
Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurements [Line Items]
Loans held for sale	20,802,000		107,633,000
Loans and leases, net	12,547,203,000		11,851,567,000
Fair Value, Measurements, Nonrecurring [Member] | Mortgage servicing assets [Member]
Fair Value Measurements [Line Items]
Mortgage servicing assets	20,983,000	[3]	14,027,000	[3]
Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value Measurements [Line Items]
Loans held for sale	0		0
Loans and leases, net	0		0
Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Mortgage servicing assets [Member]
Fair Value Measurements [Line Items]
Mortgage servicing assets	0	[3]	0	[3]
Fair Value, Measurements, Nonrecurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Measurements [Line Items]
Loans held for sale	20,802,000		0
Loans and leases, net	0		0
Fair Value, Measurements, Nonrecurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Mortgage servicing assets [Member]
Fair Value Measurements [Line Items]
Mortgage servicing assets	0	[3]	0	[3]
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurements [Line Items]
Loans held for sale	0		107,633,000
Loans and leases, net	12,515,714,000		12,005,555,000
Mortgage servicing assets	29,150,000
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Mortgage servicing assets [Member]
Fair Value Measurements [Line Items]
Mortgage servicing assets	$ 29,150,000	[3]	$ 15,881,000	[3]

[1] The carrying amount of FHLB advances is net of $61 thousand and $85 thousand in hedge accounting adjustments and discounts at December 31, 2013 and December 31, 2012, respectively. The estimated fair value does not include such adjustments.

[2] The carrying amount of long-term debt is net of $1.0 million and $4.4 million in hedge accounting adjustments and discounts at December 31, 2013 and December 31, 2012, respectively. The estimated fair value does not include such adjustments.

[3] The carrying amount of mortgage servicing assets is net of $0.2 million and $1.8 million reserves at December 31, 2013 and December 31, 2012, respectively. The estimated fair value does not include such adjustments.