XML 80 R69.htm IDEA: XBRL DOCUMENT v3.10.0.1
Debt - Cabot Senior Revolving Credit Facility (Details)
12 Months Ended
Nov. 11, 2015
GBP (£)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2017
GBP (£)
Dec. 12, 2017
USD ($)
Dec. 12, 2017
GBP (£)
Sep. 20, 2012
GBP (£)
Debt Instrument [Line Items]              
Weighted average interest rate   4.03% 3.56%        
Cabot Credit Agreement              
Debt Instrument [Line Items]              
Revolving credit facility             £ 50,000,000.0
Revolving Credit Facility              
Debt Instrument [Line Items]              
Revolving credit facility | $   $ 794,600,000.0          
Cabot senior revolving credit facility              
Debt Instrument [Line Items]              
Maximum loan to value ratio 0.75%            
Outstanding borrowings for credit facility | $   $ 179,008,000 $ 33,218,000        
Weighted average interest rate   3.60% 3.95%        
Senior Loans | Cabot senior revolving credit facility              
Debt Instrument [Line Items]              
Maximum loan to value ratio 25.00%            
LIBOR | Cabot senior revolving credit facility              
Debt Instrument [Line Items]              
Debt instrument, initial spread percentage 3.25%            
Debt instrument, alternate basis spread on variable rate 2.75%            
LIBOR | Minimum              
Debt Instrument [Line Items]              
Debt instrument, initial spread percentage   2.50%          
Cabot Credit Agreement, Tranche with Expiration in September 2019 | Secured Debt | Revolving Credit Facility              
Debt Instrument [Line Items]              
Revolving credit facility       £ 245,000,000   £ 245,000,000.0  
Cabot Credit Agreement | Secured Debt              
Debt Instrument [Line Items]              
Revolving credit facility £ 250,000,000.0       $ 395,200,000 £ 295,000,000  
Cabot Credit Agreement | Secured Debt | Revolving Credit Facility              
Debt Instrument [Line Items]              
Maximum utilization of credit facility   20.00%          
Cabot Credit Agreement | Senior Loans | Revolving Credit Facility              
Debt Instrument [Line Items]              
Maximum utilization of credit facility 20.00%            
Cabot Credit Agreement, Tranche with Expiration in March 2022 | Secured Debt | Revolving Credit Facility              
Debt Instrument [Line Items]              
Revolving credit facility       £ 50,000,000.0