Fair Value Measurements - Assets and Liabilities Reported on Consolidated Statements of Financial Condition at Fair Values (Detail) (USD $) | Jun. 30, 2014 | Dec. 31, 2013 |
In Thousands, unless otherwise specified |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | $1,156,986 | $1,157,594 |
Measured on a non-recurring basis: | ' | ' |
Foreclosed assets | 6,983 | 5,486 |
Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 1,156,986 | 1,157,594 |
Measured on a Non-Recurring Basis [Member] | ' | ' |
Measured on a non-recurring basis: | ' | ' |
Loans measured for impairment based on the fair value of the underlying collateral | 27,548 | 29,782 |
Foreclosed assets | 6,983 | 5,486 |
Fair value, Measured on a non-recurring basis | 34,531 | 35,268 |
Agency Obligations [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 91,208 | 93,416 |
Mortgage-Backed Securities [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 1,048,024 | 1,054,974 |
Mortgage-Backed Securities [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 1,048,024 | 1,054,974 |
State and Municipal Obligations [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 7,699 | 8,758 |
State and Municipal Obligations [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 7,699 | 8,758 |
Corporate Obligations [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 9,539 | ' |
Equity Securities [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 516 | 446 |
Equity Securities [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 516 | 446 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 91,724 | 93,862 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 91,724 | 93,862 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Measured on a Non-Recurring Basis [Member] | ' | ' |
Measured on a non-recurring basis: | ' | ' |
Loans measured for impairment based on the fair value of the underlying collateral | 0 | 0 |
Foreclosed assets | 0 | 0 |
Fair value, Measured on a non-recurring basis | 0 | 0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Agency Obligations [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 91,208 | 93,416 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Agency Obligations [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 91,208 | 93,416 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mortgage-Backed Securities [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | 0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mortgage-Backed Securities [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | 0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | State and Municipal Obligations [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | 0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | State and Municipal Obligations [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | 0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Corporate Obligations [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | ' |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Corporate Obligations [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | ' |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Securities [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 516 | 446 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Securities [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 516 | 446 |
Significant Other Observable Inputs (Level 2) [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 1,065,262 | 1,063,732 |
Significant Other Observable Inputs (Level 2) [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 1,065,262 | 1,063,732 |
Significant Other Observable Inputs (Level 2) [Member] | Measured on a Non-Recurring Basis [Member] | ' | ' |
Measured on a non-recurring basis: | ' | ' |
Loans measured for impairment based on the fair value of the underlying collateral | 0 | 0 |
Foreclosed assets | 0 | 0 |
Fair value, Measured on a non-recurring basis | 0 | 0 |
Significant Other Observable Inputs (Level 2) [Member] | Agency Obligations [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | 0 |
Significant Other Observable Inputs (Level 2) [Member] | Agency Obligations [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | 0 |
Significant Other Observable Inputs (Level 2) [Member] | Mortgage-Backed Securities [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 1,048,024 | 1,054,974 |
Significant Other Observable Inputs (Level 2) [Member] | Mortgage-Backed Securities [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 1,048,024 | 1,054,974 |
Significant Other Observable Inputs (Level 2) [Member] | State and Municipal Obligations [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 7,699 | 8,758 |
Significant Other Observable Inputs (Level 2) [Member] | State and Municipal Obligations [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 7,699 | 8,758 |
Significant Other Observable Inputs (Level 2) [Member] | Corporate Obligations [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 9,539 | ' |
Significant Other Observable Inputs (Level 2) [Member] | Corporate Obligations [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 9,539 | ' |
Significant Other Observable Inputs (Level 2) [Member] | Equity Securities [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | 0 |
Significant Other Observable Inputs (Level 2) [Member] | Equity Securities [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | 0 |
Significant Unobservable Inputs (Level 3) [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | 0 |
Significant Unobservable Inputs (Level 3) [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | 0 |
Significant Unobservable Inputs (Level 3) [Member] | Measured on a Non-Recurring Basis [Member] | ' | ' |
Measured on a non-recurring basis: | ' | ' |
Loans measured for impairment based on the fair value of the underlying collateral | 27,548 | 29,782 |
Foreclosed assets | 6,983 | 5,486 |
Fair value, Measured on a non-recurring basis | 34,531 | 35,268 |
Significant Unobservable Inputs (Level 3) [Member] | Agency Obligations [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | 0 |
Significant Unobservable Inputs (Level 3) [Member] | Agency Obligations [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | 0 |
Significant Unobservable Inputs (Level 3) [Member] | Mortgage-Backed Securities [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | 0 |
Significant Unobservable Inputs (Level 3) [Member] | Mortgage-Backed Securities [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | 0 |
Significant Unobservable Inputs (Level 3) [Member] | State and Municipal Obligations [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | 0 |
Significant Unobservable Inputs (Level 3) [Member] | State and Municipal Obligations [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | 0 |
Significant Unobservable Inputs (Level 3) [Member] | Corporate Obligations [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | ' |
Significant Unobservable Inputs (Level 3) [Member] | Corporate Obligations [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | ' |
Significant Unobservable Inputs (Level 3) [Member] | Equity Securities [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | 0 | 0 |
Significant Unobservable Inputs (Level 3) [Member] | Equity Securities [Member] | Measured on a Recurring Basis [Member] | ' | ' |
Securities available for sale: | ' | ' |
Securities available for sale, at fair value | $0 | $0 |