Convertible Notes (Interest Expense for the Series 2012 Notes) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument [Line Items]
Amortization of debt discount	$ 11,159	$ 10,170
Series 2012 Notes [Member]
Debt Instrument [Line Items]
Contractual coupon interest	5,158	5,122	0
Amortization of debt issuance costs	1,152	1,107	0
Amortization of debt discount	6,102	5,682	0
Total	$ 12,412	$ 11,911	$ 0