Schedule I Condensed Parent Company Financial Statements (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 275,004	$ 554,831	$ 598,108	$ 515,164
Prepaid expenses and other	24,766	25,278
Total current assets	734,148	1,010,476
Deferred financing costs, net of accumulated amortization of accumulated amortization of $8,475 and $6,404, respectively	7,986	2,846
Total assets	3,203,050	2,926,859
Current liabilities:
Accounts payable	295,689	184,400
Accrued liabilities	159,897	201,967
Total current liabilities	456,741	448,771
Long-term debt	$ 860,878	$ 748,362
Shareholders' equity:
Preference shares, $0.01 par value; 2,000,000,000 authorized shares; 393,902,63 and 392,443,048 issued at December 31, 2015 and 2014, respectively
Common shares, $0.01 par value; 2,000,000,000 authorized shares; 393,902,643 and 392,443,048 issued at December 31, 2015 and 2014, respectively	$ 3,939	$ 3,924
Additional paid-in capital	1,933,189	1,860,190
Accumulated deficit	(564,686)	(494,850)
Accumulated other comprehensive income	0	767
Treasury stock, at cost, 8,812,054 and 5,555,088 shares at December 31, 2015 and December 31, 2014, respectively	(46,929)	(31,072)
Total shareholders' equity	1,325,513	1,338,959	992,335	1,028,906
Total liabilities and shareholders' equity	$ 3,203,050	2,926,859
Parent company
Investment in subsidiaries (as a percent)	100.00%
Current assets:
Cash and cash equivalents	$ 74,683	165,894	$ 35,092	$ 132,574
Receivables from subsidiaries		154
Prepaid expenses and other	469	435
Total current assets	75,152	166,483
Investment in subsidiaries at equity	1,759,419	1,474,105
Deferred financing costs, net of accumulated amortization of accumulated amortization of $8,475 and $6,404, respectively	7,986	2,846
Total assets	1,842,557	1,643,434
Current liabilities:
Accounts payable	11
Accounts payable to subsidiaries	1,070
Accrued liabilities	17,629	11,523
Total current liabilities	18,710	11,523
Long-term debt	498,334	292,952
Shareholders' equity:
Common shares, $0.01 par value; 2,000,000,000 authorized shares; 393,902,643 and 392,443,048 issued at December 31, 2015 and 2014, respectively	3,939	3,924
Additional paid-in capital	1,933,189	1,860,190
Accumulated deficit	(564,686)	(494,850)
Accumulated other comprehensive income		767
Treasury stock, at cost, 8,812,054 and 5,555,088 shares at December 31, 2015 and December 31, 2014, respectively	(46,929)	(31,072)
Total shareholders' equity	1,325,513	1,338,959
Total liabilities and shareholders' equity	$ 1,842,557	$ 1,643,434