CONSOLIDATED STATEMENTS OF FINANCIAL POSITION (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Accounts receivable, less allowance for doubtful accounts	$ 1,655	$ 1,773
Property, plant and equipment, accumulated depreciation	$ 222,189	$ 205,575
Capital Stock, par value	$ 1	$ 1
Capital Stock, authorized shares	50,000,000	50,000,000
Capital Stock, shares outstanding	17,854,506	16,904,441