CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Mar. 31, 2012	Dec. 31, 2011
Stockholders' equity:
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	144,390	144,000
Common stock, shares issued	70,561	69,394
Treasury stock at cost (shares)	115	115