Fair Value - Assets and Liabilities Reported on Consolidated Statements of Financial Condition at Fair Value on a Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	$ 1,067,401	$ 1,110,776
U.S. Sponsored Entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	631,071	649,933
Private Label [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,956	4,316
Trust Preferred Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	38,488	38,027
Municipal Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	179,437	190,887
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,729	1,818
Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	214,720	225,795
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level I) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,729	1,818
Significant Other Observable Inputs (Level II) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,028,904	1,072,779
Significant Unobservable Inputs (Level III) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	36,768	36,179
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,067,401	1,110,776
Mortgage backed securities	633,027	654,249
Total other assets	638	90
Total other liabilities	4,258	5,743
Fair Value, Measurements, Recurring [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other liabilities	4,258	5,743
Fair Value, Measurements, Recurring [Member] | Interest Rate Caps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other assets	638	90
Fair Value, Measurements, Recurring [Member] | U.S. Sponsored Entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage backed securities	631,071	649,933
Fair Value, Measurements, Recurring [Member] | Private Label [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage backed securities	1,956	4,316
Fair Value, Measurements, Recurring [Member] | Trust Preferred Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	38,488	38,027
Fair Value, Measurements, Recurring [Member] | Municipal Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	179,437	190,887
Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,729	1,818
Fair Value, Measurements, Recurring [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	214,720	225,795
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level I) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,729	1,818
Mortgage backed securities
Total other assets
Total other liabilities
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level I) [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other liabilities
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level I) [Member] | Interest Rate Caps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other assets
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level I) [Member] | U.S. Sponsored Entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage backed securities
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level I) [Member] | Private Label [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage backed securities
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level I) [Member] | Trust Preferred Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level I) [Member] | Municipal Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level I) [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,729	1,818
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level I) [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level II) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,028,904	1,072,779
Mortgage backed securities	633,027	654,249
Total other assets	638	90
Total other liabilities	4,258	5,743
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level II) [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other liabilities	4,258	5,743
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level II) [Member] | Interest Rate Caps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other assets	638	90
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level II) [Member] | U.S. Sponsored Entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage backed securities	631,071	649,933
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level II) [Member] | Private Label [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage backed securities	1,956	4,316
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level II) [Member] | Trust Preferred Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,720	1,848
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level II) [Member] | Municipal Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	179,437	190,887
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level II) [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level II) [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	214,720	225,795
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level III) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	36,768	36,179
Mortgage backed securities
Total other assets
Total other liabilities
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level III) [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other liabilities
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level III) [Member] | Interest Rate Caps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other assets
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level III) [Member] | U.S. Sponsored Entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage backed securities
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level III) [Member] | Private Label [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage backed securities
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level III) [Member] | Trust Preferred Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	36,768	36,179
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level III) [Member] | Municipal Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level III) [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level III) [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale