Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Statement of Financial Position [Abstract]
Common stock, par value per share	$ 0.1	$ 0.1	$ 0.1
Common stock, shares authorized	80,000,000	80,000,000	80,000,000
Common stock, shares issued	30,235,164	30,235,164	30,235,164
Treasury shares, at cost	2,140,368	2,224,902	1,713,387