Fair Value Measurements (Carrying Values and Estimated Fair Values of Financial Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Financial Assets:
Securities held-to-maturity	$ 2,156,882	$ 2,133,804
FHLB-NY stock	138,384	140,754
MSR, net	11,463	11,401
Level 2 fair value
Financial Assets:
Securities held-to-maturity	2,152,091	2,131,371
FHLB-NY stock	138,384	140,754
Financial Liabilities:
Deposits	9,253,520	9,534,918
Borrowings, net	4,264,239	4,395,604
Level 3 fair value
Financial Assets:
Loans held-for-sale, net	8,354	7,955
Loans Receivable, Fair Value Disclosure	11,466,373	11,967,608
MSR, net	11,466	11,406
Carrying value
Financial Assets:
Securities held-to-maturity	2,156,882	2,133,804
FHLB-NY stock	138,384	140,754
Loans held-for-sale, net	8,318	7,640
Loans Receivable, Fair Value Disclosure	11,406,556	11,845,848
MSR, net	11,463	11,401
Financial Liabilities:
Deposits	9,227,770	9,504,909
Borrowings, net	4,058,957	4,187,691
Estimate of Fair Value Measurement [Member]
Financial Assets:
Securities held-to-maturity	2,152,091	2,131,371
FHLB-NY stock	138,384	140,754
Loans held-for-sale, net	8,354	7,955
Loans Receivable, Fair Value Disclosure	11,466,373	11,967,608
MSR, net	11,466	11,406
Financial Liabilities:
Deposits	9,253,520	9,534,918
Borrowings, net	$ 4,264,239	$ 4,395,604