Long-Term Investments and Other Assets - Additional Information (Detail) (USD $) In Millions, unless otherwise specified			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Minimum [Member]	Dec. 31, 2012 Maximum [Member]
Schedule Of Long Term Prepayment Deposits And Other Assets [Line Items]
Shares are amortized on a straight-line basis			1 year	5 years
Deferred Commissions	$ 5.9	$ 5.7
Capital Lease Obligations and Other Long Term Liabilities	$ 3.0	$ 2.8