CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
CONSOLIDATED BALANCE SHEETS
Accounts receivable, allowances (in dollars)	$ 2,786	$ 2,499
Other current assets, restricted cash (in dollars)	1,932	1,917
Other non-current assets, restricted cash (in dollars)	$ 4,005	$ 4,178
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, Authorized shares	15,000	15,000
Preferred stock, issued shares	0	0
Preferred stock, outstanding shares	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, Authorized shares	200,000	200,000
Common stock, issued shares	29,173	29,163
Common stock, outstanding shares	27,669	27,659