Joint Ventures (Detail) (USD $)	3 Months Ended		9 Months Ended		57 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Dec. 31, 2011
Schedule of Equity Method Investments [Line Items]
Accumulated stock-based compensation contributed to joint venture					$ 13,200,000
Consolidated ownership perentage of outstanding equity	58.00%		58.00%		58.00%
Capital contribution			217,881,000	191,624,000	667,200,000
Consolidated share of losses	63.20%	63.20%	63.20%	63.20%
Loss From VCE	61,900,000	50,200,000	176,900,000	138,700,000	430,200,000
Revenue recognized from sales to VCE	65,300,000	41,900,000	210,800,000	86,400,000
Receivable from joint venture	$ 28,800,000		$ 28,800,000		$ 28,800,000	$ 27,000,000