Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Restricted Cash and Cash Equivalents, Current		$ 200
Marketable securities, restricted securities	220	57
Accounts receivable, net of reserves	4,677	3,807
Marketable securities, restricted securities	$ 54	$ 43
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares designated as Series A Junior Participating Preferred Stock (in shares)	700,000	700,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	700,000,000	700,000,000
Common stock, shares issued (in shares)	201,351,880	200,199,536
Common stock, shares outstanding (in shares)	177,840,407	177,782,814
Treasury stock, shares (in shares)	23,511,473	22,416,722