Consolidated Statements of Condition (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Allowance for loan losses	$ 40,845	$ 39,426
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	65,000,000	65,000,000
Common stock, issued	55,888,833	55,697,124
Treasury stock, shares	27,979,607	27,489,288