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	Sep. 30, 2014	Dec. 31, 2013
Financial Assets:
Securities held-to-maturity	$ 493,059	$ 495,082
Financial Liabilities:
Time deposits	211,303	217,943
Securities sold under agreements to repurchase with retail customers	61,457	68,304
Book Value [Member]
Financial Assets:
Cash and due from banks	27,657	33,958
Securities held-to-maturity	486,819	495,599
Federal Home Loan Bank of New York stock	14,785	14,518
Loans receivable and mortgage loans held for sale	1,635,122	1,542,245
Financial Liabilities:
Deposits other than time deposits	1,569,924	1,528,820
Time deposits	211,303	217,943
Securities sold under agreements to repurchase with retail customers	61,457	68,304
Federal Home Loan Bank advances and other borrowings	232,696	202,500
Level 1 Inputs [Member]
Financial Assets:
Cash and due from banks	27,657	33,958
Financial Liabilities:
Securities sold under agreements to repurchase with retail customers	61,457	68,304
Level 2 Inputs [Member]
Financial Assets:
Securities held-to-maturity	492,459	493,432
Financial Liabilities:
Deposits other than time deposits	1,569,924	1,528,820
Time deposits	212,836	220,409
Federal Home Loan Bank advances and other borrowings	231,166	201,393
Level 3 Inputs [Member]
Financial Assets:
Securities held-to-maturity	600	1,650
Federal Home Loan Bank of New York stock	14,785	14,518
Loans receivable and mortgage loans held for sale	$ 1,645,687	$ 1,561,208