Balance Sheet Parenthetical (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Held-To-Maturity Securities, at Fair Value	$ 335,901	$ 343,751
Preferred Stock, Par Value	$ 5	$ 5
Preferred Stock, Shares Authorized	1,000,000	1,000,000
Common Stock, Par Value	$ 1	$ 1
Common Stock, Shares Authorized	20,000,000	20,000,000
Common Stock, Shares Issued	18,481,301	17,943,201
Unallocated ESOP Shares - Shares	9,643	19,466
Treasury Stock, Shares	4,541,524	4,441,093