Supplemental Cash Flow Supplemental Cash Flow (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplemental Cash Flow Information [Abstract]
Income Taxes Paid			$ (81,962,000)
Interest Paid, Net	$ 186,924,000	$ 207,094,000	233,631,000
Proceeds from Income Tax Refunds	(18,032,000)	(59,584,000)
Capital Lease Obligations [Member]
Other Significant Noncash Transactions [Line Items]
Noncash or Part Noncash Acquisition, Value of Liabilities Assumed	55	4,973	1,540
Notes Received from Property Sales [Member]
Other Significant Noncash Transactions [Line Items]
Other Significant Noncash Transaction, Value of Consideration Received	$ 6,706	$ 24,347	$ 68,800