Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Consolidated Balance Sheets [Abstract]
Common stock, par value per share	$ 0.10	$ 0.10	$ 0.10
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	1,713,387	1,351,712	888,336