Convertible Senior Notes Due 2017 (Interest Expense Expected To Be Recorded In Consolidated Statement Of Operations) (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Interest Expense [Line Items]
Expected interest expense, Total	$ 101,786
Expected interest expense, Non-Cash Amortization of Debt Discount	65,670
Expected interest expense, Non-Cash Amortization of Debt Issuance Costs	5,551
Expected interest expense, Interest at Coupon Rate of 2.625%	30,565
Remainder Of 2012 [Member]
Interest Expense [Line Items]
Expected interest expense, Total	4,871
Expected interest expense, Non-Cash Amortization of Debt Discount	2,926
Expected interest expense, Non-Cash Amortization of Debt Issuance Costs	247
Expected interest expense, Interest at Coupon Rate of 2.625%	1,698
2013 [Member]
Interest Expense [Line Items]
Expected interest expense, Total	20,250
Expected interest expense, Non-Cash Amortization of Debt Discount	12,409
Expected interest expense, Non-Cash Amortization of Debt Issuance Costs	1,049
Expected interest expense, Interest at Coupon Rate of 2.625%	6,792
2014 [Member]
Interest Expense [Line Items]
Expected interest expense, Total	21,689
Expected interest expense, Non-Cash Amortization of Debt Discount	13,736
Expected interest expense, Non-Cash Amortization of Debt Issuance Costs	1,161
Expected interest expense, Interest at Coupon Rate of 2.625%	6,792
2015 [Member]
Interest Expense [Line Items]
Expected interest expense, Total	23,285
Expected interest expense, Non-Cash Amortization of Debt Discount	15,207
Expected interest expense, Non-Cash Amortization of Debt Issuance Costs	1,286
Expected interest expense, Interest at Coupon Rate of 2.625%	6,792
2016 [Member]
Interest Expense [Line Items]
Expected interest expense, Total	25,125
Expected interest expense, Non-Cash Amortization of Debt Discount	16,904
Expected interest expense, Non-Cash Amortization of Debt Issuance Costs	1,429
Expected interest expense, Interest at Coupon Rate of 2.625%	6,792
2017 [Member]
Interest Expense [Line Items]
Expected interest expense, Total	6,566
Expected interest expense, Non-Cash Amortization of Debt Discount	4,488
Expected interest expense, Non-Cash Amortization of Debt Issuance Costs	379
Expected interest expense, Interest at Coupon Rate of 2.625%	$ 1,699