Supplemental Cash Flow Information (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Supplemental Cash Flow Information [Line Items]
Interest paid	$ 368,437	$ 356,421
Income taxes paid	15,353	12,769
Increase (decrease) in accounts payable for purchases of property and equipment	2,827	(8,207)
Purchase of property and equipment under capital leases and installment purchases	$ 27,772	$ 36,756