CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
ASSETS
Securities—trading, amortized cost basis	$ 27,340	$ 27,246
Securities—available-for-sale, amortized cost basis	1,451,897	926,112
Securities—held-to-maturity, fair value	$ 254,094	$ 262,188
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	32,327,824	32,626,456
Common stock, shares outstanding	32,327,824	32,626,456
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	74,933	100,029
Common stock, shares outstanding	74,933	100,029
Loans [Member] | Recurring [Member]
ASSETS
Loans Held-for-sale, Fair Value Disclosure	$ 67,128	$ 32,392