CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Restricted cash	$ 813	$ 813
Accounts receivable, allowance for doubtful accounts and sales returns	14,159	14,074
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization on intangible assets	42,472
Shareholders' equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	93,398,840	93,137,737
Common stock, shares outstanding (in shares)	93,398,840	93,137,737
Common stock subscribed, shares (in shares)	149,341	158,395
Purchased and Developed Software [Member]
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization on intangible assets	13,983	13,884
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization on intangible assets	$ 27,425	$ 25,007