Carrying Amounts and Fair Values of Financial Instruments (Detail) (USD $) In Thousands	Jun. 30, 2011		Dec. 31, 2010
Financial Assets:
Repurchase agreements			$ 51,540
Securities held-to-maturity	1,966,836		2,003,784
FHLB-NY stock	129,025		149,174
Loans held-for-sale, net	15,393		44,870
Loans receivable, net	13,324,862		14,021,548
MSR, net	9,356		9,204
Financial Liabilities:
Deposits	11,210,620		11,599,000
Carrying Amount
Financial Assets:
Repurchase agreements			51,540
Securities held-to-maturity	1,966,836		2,003,784
FHLB-NY stock	129,025		149,174
Loans held-for-sale, net	15,393	[1]	44,870	[1]
Loans receivable, net	13,324,862	[1]	14,021,548	[1]
MSR, net	9,356	[1]	9,204	[1]
Financial Liabilities:
Deposits	11,210,620		11,599,000
Borrowings, net	4,286,389		4,869,204
Estimated Fair Value
Financial Assets:
Repurchase agreements			51,540
Securities held-to-maturity	2,014,151		2,042,110
FHLB-NY stock	129,025		149,174
Loans held-for-sale, net	15,536	[1]	45,713	[1]
Loans receivable, net	13,700,880	[1]	14,480,713	[1]
MSR, net	9,362	[1]	9,214	[1]
Financial Liabilities:
Deposits	11,393,588		11,784,632
Borrowings, net	$ 4,838,940		$ 5,320,510

[1] Includes totals for assets measured at fair value on a non-recurring basis as disclosed in Note 9.