Borrowings (Details 8) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Borrowings
Total interest expense on borrowings	$ 98,707	$ 113,911	$ 154,219
Reverse repurchase agreements
Borrowings
Total interest expense on borrowings	42,626	45,272	61,855
FHLB advances | FHLB-NY advances
Borrowings
Total interest expense on borrowings	41,911	50,654	62,675
Other borrowings
Borrowings
Total interest expense on borrowings	13,031	17,398	29,689
Federal funds purchased
Borrowings
Total interest expense on borrowings	$ 1,139	$ 587