Fair Value Measurements - Book Value and Estimated Fair Value of Bank's Significant Financial Instruments Not Recorded at Fair Value (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Financial Liabilities:
Securities sold under agreements to repurchase with retail customers	$ 71,041	$ 60,791
Book Value [Member]
Financial Assets:
Cash and due from banks	42,377	62,544
Federal Home Loan Bank of New York stock	18,890	17,061
Loans receivable and mortgage loans held for sale	1,508,495	1,529,946
Financial Liabilities:
Deposits other than time deposits	1,491,550	1,493,453
Time deposits	212,196	226,218
Securities sold under agreements to repurchase with retail customers	71,041	60,791
Federal Home Loan Bank advances and other Borrowings	296,900	252,500
Level 1 Inputs [Member]
Financial Assets:
Cash and due from banks	42,377	62,544
Federal Home Loan Bank of New York stock
Loans receivable and mortgage loans held for sale
Financial Liabilities:
Deposits other than time deposits
Time deposits
Securities sold under agreements to repurchase with retail customers	71,041	60,791
Federal Home Loan Bank advances and other Borrowings
Level 2 Inputs [Member]
Financial Assets:
Cash and due from banks
Federal Home Loan Bank of New York stock
Loans receivable and mortgage loans held for sale
Financial Liabilities:
Deposits other than time deposits	1,491,550	1,493,453
Time deposits	215,296	231,445
Securities sold under agreements to repurchase with retail customers
Federal Home Loan Bank advances and other Borrowings	300,310	258,577
Level 3 Inputs [Member]
Financial Assets:
Cash and due from banks
Federal Home Loan Bank of New York stock	18,890	17,061
Loans receivable and mortgage loans held for sale	1,524,429	1,572,291
Financial Liabilities:
Deposits other than time deposits
Time deposits
Securities sold under agreements to repurchase with retail customers
Federal Home Loan Bank advances and other Borrowings