Fair Value Measurements (Carrying Values and Estimated Fair Values of Financial Instruments) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Financial Assets:
Securities held-to-maturity	$ 2,197,629	$ 2,133,804
FHLB-NY stock	128,687	140,754
MSR, net	10,488	11,401
Level 2 fair value
Financial Assets:
Securities held-to-maturity	2,215,444	2,131,371
FHLB-NY stock	128,687	140,754
Financial Liabilities:
Deposits	9,082,148	9,534,918
Borrowings, net	4,215,025	4,395,604
Level 3 fair value
Financial Assets:
Loans held-for-sale, net	5,951	7,955
Loans Receivable, Fair Value Disclosure	11,200,091	11,967,608
MSR, net	10,489	11,406
Carrying value
Financial Assets:
Securities held-to-maturity	2,197,629	2,133,804
FHLB-NY stock	128,687	140,754
Loans held-for-sale, net	5,918	7,640
Loans Receivable, Fair Value Disclosure	11,149,872	11,845,848
MSR, net	10,488	11,401
Financial Liabilities:
Deposits	9,048,461	9,504,909
Borrowings, net	4,006,089	4,187,691
Estimate of Fair Value Measurement [Member]
Financial Assets:
Securities held-to-maturity	2,215,444	2,131,371
FHLB-NY stock	128,687	140,754
Loans held-for-sale, net	5,951	7,955
Loans Receivable, Fair Value Disclosure	11,200,091	11,967,608
MSR, net	10,489	11,406
Financial Liabilities:
Deposits	9,082,148	9,534,918
Borrowings, net	$ 4,215,025	$ 4,395,604