Fair Value Measurements (Fair Value Assets And Liabilities Measured On Recurring Basis) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	$ 3,120,354	$ 2,874,764
Total financial assets held at fair value	3,185,483	2,924,739
Total financial liabilities held at fair value	64,096	59,791
Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - assets	56,485	47,134
Derivative instruments - liabilities	63,646	58,424
Mortgage Banking Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - assets	1,323
Investments Held In Rabbi Trust [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - assets	5,706
Investments In Private Equity Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - assets	1,615	2,841
Fed Fund Futures Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - liabilities	447	1,365
Visa Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - liabilities	3	2
U.S. Treasury Bills [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	200	200
Agency CMOs - GSE [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	1,474,210	1,940,242
Corporate Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	118,138
Pooled Trust Preferred Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	28,253	28,998
Single Issuer Trust Preferred Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	41,420	38,214
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	8,295	9,447
Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	1,069,217	527,310
CMBS [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	380,621	330,353
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	8,295	8,672
Derivative instruments - assets	0	0
Total financial assets held at fair value	14,001	8,672
Derivative instruments - liabilities	447	0
Total financial liabilities held at fair value	447	0
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - assets		0
Derivative instruments - liabilities		0
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Mortgage Banking Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - assets
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Investments Held In Rabbi Trust [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - assets	5,706
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Investments In Private Equity Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - assets		0
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Fed Fund Futures Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - liabilities	447	0
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Visa Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - liabilities		0
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | U.S. Treasury Bills [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	200	200
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Agency CMOs - GSE [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		0
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Corporate Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Pooled Trust Preferred Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		0
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Single Issuer Trust Preferred Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		0
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	8,095	8,472
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		0
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | CMBS [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		0
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	3,083,806	2,836,119
Derivative instruments - assets	56,485	47,134
Total financial assets held at fair value	3,141,614	2,883,253
Derivative instruments - liabilities	63,649	59,791
Total financial liabilities held at fair value	63,649	59,791
Significant Other Observable Inputs (Level 2) [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - assets	56,485	47,134
Derivative instruments - liabilities	63,646	58,424
Significant Other Observable Inputs (Level 2) [Member] | Mortgage Banking Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - assets	1,323
Significant Other Observable Inputs (Level 2) [Member] | Investments Held In Rabbi Trust [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - assets
Significant Other Observable Inputs (Level 2) [Member] | Investments In Private Equity Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - assets		0
Significant Other Observable Inputs (Level 2) [Member] | Fed Fund Futures Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - liabilities		1,365
Significant Other Observable Inputs (Level 2) [Member] | Visa Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - liabilities	3	2
Significant Other Observable Inputs (Level 2) [Member] | U.S. Treasury Bills [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		0
Significant Other Observable Inputs (Level 2) [Member] | Agency CMOs - GSE [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	1,474,210	1,940,242
Significant Other Observable Inputs (Level 2) [Member] | Corporate Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	118,138
Significant Other Observable Inputs (Level 2) [Member] | Pooled Trust Preferred Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		0
Significant Other Observable Inputs (Level 2) [Member] | Single Issuer Trust Preferred Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	41,420	38,214
Significant Other Observable Inputs (Level 2) [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	200	0
Significant Other Observable Inputs (Level 2) [Member] | Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	1,069,217	527,310
Significant Other Observable Inputs (Level 2) [Member] | CMBS [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	380,621	330,353
Significant Unobservable Input (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	28,253	29,973
Derivative instruments - assets	0	0
Total financial assets held at fair value	29,868	32,814
Derivative instruments - liabilities	0	0
Total financial liabilities held at fair value		0
Significant Unobservable Input (Level 3) [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - assets		0
Derivative instruments - liabilities		0
Significant Unobservable Input (Level 3) [Member] | Mortgage Banking Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - assets
Significant Unobservable Input (Level 3) [Member] | Investments Held In Rabbi Trust [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - assets
Significant Unobservable Input (Level 3) [Member] | Investments In Private Equity Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - assets	1,615	2,841
Significant Unobservable Input (Level 3) [Member] | Fed Fund Futures Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - liabilities		0
Significant Unobservable Input (Level 3) [Member] | Visa Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments - liabilities		0
Significant Unobservable Input (Level 3) [Member] | U.S. Treasury Bills [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		0
Significant Unobservable Input (Level 3) [Member] | Agency CMOs - GSE [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		0
Significant Unobservable Input (Level 3) [Member] | Corporate Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value
Significant Unobservable Input (Level 3) [Member] | Pooled Trust Preferred Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	28,253	28,998
Significant Unobservable Input (Level 3) [Member] | Single Issuer Trust Preferred Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		0
Significant Unobservable Input (Level 3) [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		975
Significant Unobservable Input (Level 3) [Member] | Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		0
Significant Unobservable Input (Level 3) [Member] | CMBS [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		$ 0