Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 1,101	$ 877
Common stock, par value	$ 1.50	$ 1.50
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	24,934,981	24,934,981
Treasury stock, shares	4,518,446	4,618,433