Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Consolidated Balance Sheets [Abstract]
Trade, allowance for doubtful accounts	$ 689	$ 806
Other, allowance for doubtful accounts	$ 332	$ 340
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	134,751,627	133,121,092
Treasury stock, shares	11,727,409	11,264,936