Equity Investments - Narrative (Details) $ / shares in Units, $ in Thousands				3 Months Ended	6 Months Ended	12 Months Ended
	Jul. 09, 2014 USD ($) $ / shares shares	May 09, 2014 USD ($) company shares	Jul. 02, 2013 $ / shares shares	Jun. 30, 2014 USD ($) $ / shares shares	Jul. 09, 2014 USD ($) $ / shares	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Jul. 03, 2013 shares
Schedule of Equity Method Investments [Line Items]
Gain on sale of equity investment						$ 0	$ 0	$ 171,561
Gain on issuance of shares by an equity investee						$ 0	$ 0	$ 17,020
AIC
Schedule of Equity Method Investments [Line Items]
Equity investments, number of shares sold (in shares) | shares		20,000
Equity investments, proceeds from sale		$ 5,800
Ownership percentage		0.00%
Amount invested in equity investee		$ 5,800
Number of other companies which are shareholders of related party | company		5
SIR
Schedule of Equity Method Investments [Line Items]
Equity investments, number of shares sold (in shares) | shares	22,000,000
Equity investments, proceeds from sale	$ 704,800
Price per common share (in dollars per share) | $ / shares	$ 32.04				$ 32.04
Gain on sale of equity investment	$ 171,800
Ownership percentage	0.00%		56.00%	36.70%	0.00%
Issuance of shares, net (in shares) | shares			10,500,000	10,000,000
Common stock price per share (in dollars per share) | $ / shares			$ 28.25	$ 29.00
Proceeds from issuance of common shares, net				$ 277,400
Gain on issuance of shares by an equity investee				$ 16,900
Equity investments, common shares owned (in shares) | shares			22,000,000						22,000,000
Less than wholly owned subsidiary, parent ownership interest percentage									44.20%
Cash distributions					$ 20,700