Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 1,249	$ 1,224
Accumulated amortization	650	9,774
Deferred Income Tax Assets, Net	3,000	2,055
Deferred income taxes	$ 20,672	$ 56,510
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	250,000,000	250,000,000
Common stock, shares issued (in shares)	120,146,720	119,606,551
Treasury stock, shares (in shares)	58,879,742	57,832,362