XML 37 R67.htm IDEA: XBRL DOCUMENT v2.4.0.6
Other Assets (Detail) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2013
Dec. 31, 2012
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]    
Debt issuance costs, net of amortization $ 69,005 $ 83,643
Restricted deposits 27,950 27,947
Notes receivable on asset retirement obligations 11,655 11,433
Investments 11,584 10,348
Production tax credit receivable 5,673 6,313
Other 2,461 4,568
Total other assets $ 128,328 $ 144,252