Schedule I Condensed Parent Company Financial Statements - Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 194,057	$ 275,004	$ 554,831
Prepaid expenses and other	7,209	24,766
Total current assets	475,187	734,148
Deferred financing costs, net of accumulated amortization of accumulated amortization of $11,213 and 8,475 at December 31, 2016 and December 31, 2015, respectively	5,248	7,986
Total assets	3,341,465	3,203,050
Current liabilities:
Accounts payable	220,627	295,689
Accrued liabilities	129,706	159,897
Total current liabilities	370,025	456,741
Long-term debt	1,321,874	860,878
Shareholders' equity:
Preference shares, $0.01 par value; 200,000,000 authorized shares; zero issued at December 31, 2016 and December 31, 2015
Common shares, $0.01 par value; 2,000,000,000 authorized shares; 395,859,061 and 393,902,643 issued at December 31, 2016 and 2015, respectively	3,959	3,939
Additional paid-in capital	1,975,247	1,933,189
Accumulated deficit	(850,410)	(564,686)
Accumulated other comprehensive income	0
Treasury stock, at cost, 9,101,395 and 8,812,054 shares at December 31, 2016 and 2015, respectively	(47,597)	(46,929)
Total shareholders' equity	1,081,199	1,325,513	1,338,959	$ 992,335
Total liabilities and shareholders' equity	$ 3,341,465	3,203,050
Parent company
Investment in subsidiaries (as a percent)	100.00%
Current assets:
Cash and cash equivalents	$ 1,092	74,683	$ 165,894	$ 35,092
Receivables from subsidiaries	14,131
Prepaid expenses and other	417	469
Total current assets	15,640	75,152
Investment in subsidiaries at equity	1,580,459	1,759,419
Deferred financing costs, net of accumulated amortization of accumulated amortization of $11,213 and 8,475 at December 31, 2016 and December 31, 2015, respectively	5,248	7,986
Total assets	1,601,347	1,842,557
Current liabilities:
Accounts payable	13	11
Accounts payable to subsidiaries		1,070
Accrued liabilities	17,939	17,629
Total current liabilities	17,952	18,710
Long-term debt	502,196	498,334
Shareholders' equity:
Common shares, $0.01 par value; 2,000,000,000 authorized shares; 395,859,061 and 393,902,643 issued at December 31, 2016 and 2015, respectively	3,959	3,939
Additional paid-in capital	1,975,247	1,933,189
Accumulated deficit	(850,410)	(564,686)
Treasury stock, at cost, 9,101,395 and 8,812,054 shares at December 31, 2016 and 2015, respectively	(47,597)	(46,929)
Total shareholders' equity	1,081,199	1,325,513
Total liabilities and shareholders' equity	$ 1,601,347	$ 1,842,557