CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
ASSETS
Securities—trading, amortized cost basis	$ 39,155	$ 39,344
Securities—available-for-sale, amortized cost basis	1,186,995	1,139,740
Securities—held-to-maturity, fair value	$ 255,823	$ 226,627
SHAREHOLDERS’ EQUITY
Preferred stock, share par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	500,000	500,000
Preferred stock, shares outstanding	0	0
Voting Common Stock [Member]
SHAREHOLDERS’ EQUITY
Common stock, share par value	$ 0.01	$ 0.01
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	32,830,675	32,817,789
Common stock, shares outstanding	32,830,675	32,817,789
Nonvoting Common Stock [Member]
SHAREHOLDERS’ EQUITY
Common stock, share par value	$ 0.01	$ 0.01
Common stock, shares authorized	5,000,000	5,000,000
Common stock, shares issued	1,390,776	1,424,466
Common stock, shares outstanding	1,390,776	1,424,466