Fair Value Measurements (Details 5) (USD $) In Thousands, unless otherwise specified			6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 Mortgage loans held-for-sale Minimum	Jun. 30, 2014 Mortgage loans held-for-sale Maximum	Jun. 30, 2014 Total Fair Value	Dec. 31, 2013 Total Fair Value	Jun. 30, 2014 Level 2 Fair Value	Dec. 31, 2013 Level 2 Fair Value	Jun. 30, 2014 Level 3 Fair Value	Dec. 31, 2013 Level 3 Fair Value	Jun. 30, 2014 Carrying Value	Dec. 31, 2013 Carrying Value
Financial Assets:
Securities held-to-maturity	$ 1,960,930	$ 1,849,526			$ 1,950,622	$ 1,811,122	$ 1,950,622	$ 1,811,122			$ 1,960,930	$ 1,849,526
FHLB-NY stock	150,288	152,207			150,288	152,207	150,288	152,207			150,288	152,207
Loans held-for-sale, net					7,309	7,436			7,309	7,436	7,204	7,375
Non-performing residential mortgage loans held-for-sale	186,312				186,312				186,312		186,312
Loans receivable, net					12,113,353	12,480,533			12,113,353	12,480,533	11,943,022	12,303,066
MSR, net	11,804	12,800			11,809	12,804			11,809	12,804	11,804	12,800
Mortgage loan, original term			15 years	30 years
Financial Liabilities:
Deposits					9,710,042	9,922,631	9,710,042	9,922,631			9,659,371	9,855,310
Borrowings, net					$ 4,432,877	$ 4,376,336	$ 4,432,877	$ 4,376,336			$ 4,200,426	$ 4,137,161