Fair Value Measurements (Fair Value Of Assets Measured On Recurring And Nonrecurring Basis) (Detail) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Recurring Items [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Cash and cash equivalents	$ 138,680	$ 94,410
Debt Security	70,338
Nonrecurring Items [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets held for sale	675	675
Convertible Senior Notes [Member] | Recurring Items [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Convertible Senior Notes	232,390	248,000
Secured Senior Notes [Member] | Recurring Items [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Convertible Senior Notes	518,400	702,700
Quoted Prices In Activated Markets For Identical Assets (Level 1) [Member] | Recurring Items [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Cash and cash equivalents	138,680	94,410
Debt Security	0
Quoted Prices In Activated Markets For Identical Assets (Level 1) [Member] | Nonrecurring Items [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets held for sale	0	0
Quoted Prices In Activated Markets For Identical Assets (Level 1) [Member] | Convertible Senior Notes [Member] | Recurring Items [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Convertible Senior Notes	232,390	248,000
Quoted Prices In Activated Markets For Identical Assets (Level 1) [Member] | Secured Senior Notes [Member] | Recurring Items [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Convertible Senior Notes	518,400	702,700
Significant Other Observable Inputs (Level 2) [Member] | Recurring Items [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Cash and cash equivalents	0	0
Debt Security	0
Significant Other Observable Inputs (Level 2) [Member] | Nonrecurring Items [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets held for sale	0	0
Significant Other Observable Inputs (Level 2) [Member] | Convertible Senior Notes [Member] | Recurring Items [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Convertible Senior Notes	0	0
Significant Other Observable Inputs (Level 2) [Member] | Secured Senior Notes [Member] | Recurring Items [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Convertible Senior Notes	0	0
Unobservable Inputs (Level 3) [Member] | Recurring Items [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Cash and cash equivalents	0	0
Debt Security	70,338
Unobservable Inputs (Level 3) [Member] | Nonrecurring Items [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets held for sale	675	675
Unobservable Inputs (Level 3) [Member] | Convertible Senior Notes [Member] | Recurring Items [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Convertible Senior Notes	0	0
Unobservable Inputs (Level 3) [Member] | Secured Senior Notes [Member] | Recurring Items [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Convertible Senior Notes	$ 0	$ 0