Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Supplemental Cash Flow Information [Line Items]
Interest paid	$ 111,469	$ 120,949
Income taxes paid	6,773	2,498
Increase (decrease) in accounts payable for purchases of property and equipment	(8,638)	(13,557)
Purchase of property and equipment under capital leases and installment purchases	$ 12,269	$ 12,407