Equity (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions					12 Months Ended
		Dec. 21, 2016	Dec. 07, 2016	Aug. 12, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Issuance of common stock from stock offerings, shares					0.0
Net proceeds from sale of common stock					$ 2,623	$ 938,268	$ 4,844
August issuance [Member]
Class of Stock [Line Items]
Issuance of common stock from stock offerings, shares				18.4
Issuance of common stock, offering price per share				$ 30.00
Net proceeds from sale of common stock				$ 530,900
December issuance [Member]
Class of Stock [Line Items]
Issuance of common stock from stock offerings, shares			10.9
Issuance of common stock, offering price per share			$ 38.25
Net proceeds from sale of common stock			$ 403,200
QStar Acquisition 2016 [Member]
Class of Stock [Line Items]
Private issuance of Common Stock for an acquisition		13.4
Fair value of equity consideration	[1]	$ 437,194

[1] The Company issued approximately 13.4 million shares of common stock, par value $0.01 per share, in a private placement to the sellers in the QStar Acquisition on December 21, 2016. The equity consideration was valued on this date using Level 1 and Level 2 inputs with a discount applied due to the lack of marketability in the near term in accordance with the Lock-Up and Registration Rights Agreement that prohibited the sale of such stock until no earlier than the 90th day after issuance.