CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
CONDENSED CONSOLIDATED BALANCE SHEETS
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	400,000	400,000
Common stock, shares issued	79,219	78,560
Common stock, shares outstanding	77,671	78,466
Treasury stock	1,548	94