Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Commitments and contingencies (Note 7)
Debt Instrument [Line Items]
Future interest payable - current	[1]	101,829	105,125
Future interest payable - long-term		$ 2,466,127	$ 2,664,211
Stockholders' equity
Preferred stock, par value		$ 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		$ 0.001	$ 0.001
Common stock, shares authorized		750,000,000
Common stock, shares issued		464,166,479	462,355,725
Treasury stock, shares		2,474,904	1,941,749
Future interest payable on senior secured notes
Debt Instrument [Line Items]
Future interest payable - current		$ 85,700	$ 85,303
Future interest payable - long-term		$ 121,982	$ 164,914

[1] Our current maturities of long-term debt as of June 30, 2019 include $85.7 million of future interest payable related to the 2021 Senior Secured Notes and 2022 Senior Secured Notes that is due within the next twelve months.