CONSOLIDATED STATEMENTS OF FINANCIAL POSITION (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accounts receivable, allowance for doubtful accounts	$ 1,773	$ 1,040
Property, plant and equipment, accumulated depreciation	$ (205,575)	$ (193,721)
Capital Stock, par value (in dollars per share)	$ 1	$ 1
Capital Stock, authorized shares	50,000,000	50,000,000
Capital Stock, shares outstanding	16,904,441	16,220,648