Consolidated Balance Sheets (Parenthetical) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Time certificates of deposit least amount	$ 100,000	$ 100,000
Securities held to maturity, fair value	$ 485,650,000	$ 478,749,000
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	75,000,000	75,000,000
Common stock, shares issued	27,005,813	26,236,352
Common stock, unvested restricted Stock awards	212,698	230,900
Shares held in rabbit trust at cost	170,036	173,378
Common Stock Outstanding
Common stock, shares outstanding	27,005,813	26,236,352