Fair Value Measurements (Details 5) (USD $) In Thousands, unless otherwise specified			6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2013 Mortgage loans held-for-sale Minimum	Jun. 30, 2013 Mortgage loans held-for-sale Maximum	Jun. 30, 2013 Total Fair Value	Dec. 31, 2012 Total Fair Value	Jun. 30, 2013 Level 2 Fair Value	Dec. 31, 2012 Level 2 Fair Value	Jun. 30, 2013 Level 3 Fair Value	Dec. 31, 2012 Level 3 Fair Value	Jun. 30, 2013 Carrying Value	Dec. 31, 2012 Carrying Value
Financial Assets:
Securities held-to-maturity	$ 1,892,883	$ 1,700,141			$ 1,882,671	$ 1,725,090	$ 1,882,671	$ 1,725,090			$ 1,892,883	$ 1,700,141
FHLB-NY stock	148,738	171,194			148,738	171,194	148,738	171,194			148,738	171,194
Loans held-for-sale, net					29,283	78,486			29,283	78,486	29,283	76,306
Loans receivable, net					12,684,258	13,311,997			12,684,258	13,311,997	12,525,182	13,078,471
MSR, net	10,177	6,947			10,180	6,948			10,180	6,948	10,177	6,947
Mortgage loan, original term			15 years	30 years
Financial Liabilities:
Deposits					10,343,246	10,588,073	10,343,246	10,588,073			10,245,332	10,443,958
Borrowings, net					$ 4,284,176	$ 4,857,989	$ 4,284,176	$ 4,857,989			$ 4,021,895	$ 4,373,496