Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands		Jun. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Current maturities of long-term debt	[1]	$ 83,458	$ 83,366
Long-term Debt and Capital Lease Obligations		$ 3,060,048	$ 2,909,732
Stockholders' equity
Preferred stock, par value (actual)		$ 0.001	$ 0.001
Preferred stock, shares authorized		25,000,000	25,000,000
Preferred stock, shares issued		0	0
Preferred stock, shares outstanding		0	0
Common stock, par value (actual)		$ 0.001	$ 0.001
Common stock, shares authorized		600,000,000	600,000,000
Common stock, shares issued		403,305,493	402,334,655
Treasury stock, shares		4,405,555	3,906,877
Future interest payable on 9% Senior Secured Second Lien Notes
Debt Instrument [Line Items]
Current maturities of long-term debt		$ 50,490	$ 50,349
Long-term Debt and Capital Lease Obligations		$ 153,196	$ 178,476

[1] Future interest payable on our 9% Senior Secured Second Lien Notes due 2021 (the “2021 Senior Secured Notes”) represents most of the interest due over the term of this obligation, which has been accounted for as debt in accordance with Financial Accounting Standards Board Codification (“FASC”) 470-60, Troubled Debt Restructuring by Debtors. Our current maturities of long-term debt as of June 30, 2017 include $50.5 million of future interest payable related to the 2021 Senior Secured Notes that is due within the next twelve months.