Borrowings - Schedule of Contractual Maturities of FHLB-NY Advances (Details) - FHLB-NY advances - Federal Home Loan Bank of New York - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
2017	$ 1,240,000
2020	850,000
Total	2,090,000	$ 2,180,000	$ 2,384,000
Borrowings due overnight	40,000
Borrowings due within 30 days	300,000
Borrowings due after 30 to 90 days	500,000
Borrowings due after 90 days	$ 400,000