Description of Business and Basis of Presentation (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Increase in accounts receivable	$ (27,100)	$ (68,140)
Increase in accounts payable and accrued liabilities	(138,481)	(120,329)
Cash used for purchases of available-for-sale securities	142,563	644,396
Cash provided by proceeds from sales/maturities of available-for-sale securities	$ 149,436	601,296
Restatement Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Increase in accounts receivable			$ 23,000
Increase in accounts payable and accrued liabilities			14,000
Increase in other noncurrent liabilities			$ 9,000
Cash used for purchases of available-for-sale securities		422,000
Cash provided by proceeds from sales/maturities of available-for-sale securities		$ 422,000