XML 127 R90.htm IDEA: XBRL DOCUMENT v3.8.0.1
Capital disclosures (Details) - USD ($)
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Disclosure of liquidity and capitalization [Line Items]      
Cash and cash equivalents $ 375,479,000 $ 223,890,000 $ 254,934,000
Undrawn credit facilities 300,000,000 300,000,000  
Total liquidity 675,479,000 523,890,000  
Total debt 1,502,271,000 1,556,206,000  
Non-controlling interests 244,347,000 208,515,000  
Shareholders’ equity 1,500,764,000 1,596,835,000  
Total capitalization $ 3,247,382,000 $ 3,361,556,000  
Total debt to capitalization (as a percent) 46.00% 46.00%  
Net debt to capitalization (as a percent) 39.00% 42.00%  
Unsecured notes      
Disclosure of liquidity and capitalization [Line Items]      
Total debt $ 1,188,163,000 $ 1,186,424,000  
Limited recourse debt facilities, including current portion      
Disclosure of liquidity and capitalization [Line Items]      
Total debt 314,108,000 $ 369,782,000  
Revolving credit facility      
Disclosure of liquidity and capitalization [Line Items]      
Notional amount $ 300,000,000    
Facilities term 5 years