Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Time certificates of deposit least amount	$ 100,000	$ 100,000
Held to Maturity, Fair Value, Total	$ 500,917,000	$ 485,650,000
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, unvested restricted Stock awards	191,181	212,698
Shares Held in Rabbi Trust	161,156	170,036
Common Stock Outstanding
Common Stock, Shares, Outstanding	27,046,768	27,005,813
Junior Subordinated Debt [Member]
Unamortized Debt Issuance Expense	$ 131,000	$ 136,000
Subordinated Debt [Member]
Unamortized Debt Issuance Expense	$ 353,000	$ 376,000