Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 1,258	$ 1,224
Property, plant and equipment, accumulated depreciation	168,644	173,699
Other intangible assets, accumulated amortization	445	9,774
Other long-term liabilities, deferred income taxes	$ 25,548	$ 59,532
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)	120,142,621	119,606,551
Treasury stock, shares (in shares)	58,871,121	57,832,362