XML 79 R68.htm IDEA: XBRL DOCUMENT v3.19.2
Indebtedness - Bank Debt - Additional Information (Detail)
3 Months Ended 6 Months Ended
Jun. 30, 2019
USD ($)
CommercialBank
Jun. 30, 2018
Jun. 30, 2019
USD ($)
CommercialBank
Jun. 30, 2018
Mar. 31, 2019
Dec. 31, 2018
USD ($)
Mar. 27, 2017
USD ($)
Debt Instrument [Line Items]              
Bank debt $ 885,286,000   $ 885,286,000     $ 932,018,000  
Bank Credit Facility              
Debt Instrument [Line Items]              
Bank Credit facility, maximum amount 4,000,000,000.0   4,000,000,000.0        
Bank Credit facility, borrowing base $ 3,000,000,000.0   $ 3,000,000,000.0       $ 3,000,000,000.0
Percentage holding of commercial banks, Maximum 5.80%   5.80%        
Number of commercial banks included in current bank group | CommercialBank 27   27        
Maturity date of loan     Apr. 13, 2023        
Bank commitments $ 2,000,000,000.0   $ 2,000,000,000.0       $ 2,000,000,000.0
Bank debt 895,000,000.0   895,000,000.0        
Undrawn letters of credit 282,700,000   282,700,000        
Borrowing capacity available under the commitment amount $ 822,300,000   $ 822,300,000        
Weighted average interest rate on the bank credit facility 4.00% 3.70% 4.00% 3.50%      
Annual rate of commitment fee paid on the undrawn balance     0.30%        
Bank Credit Facility | Alternate Base Rate              
Debt Instrument [Line Items]              
Interest rate margin     0.50%        
Bank Credit Facility | LIBOR Rate              
Debt Instrument [Line Items]              
Interest rate margin     1.50%        
Bank Credit Facility | Minimum              
Debt Instrument [Line Items]              
Annual rate of commitment fee paid on the undrawn balance     0.30%        
Bank Credit Facility | Minimum | Credit Facility              
Debt Instrument [Line Items]              
Annual rate of commitment fee paid on the undrawn balance     0.15%        
Bank Credit Facility | Minimum | Alternate Base Rate              
Debt Instrument [Line Items]              
Base rate on debt 0.25%   0.25%        
Bank Credit Facility | Minimum | Alternate Base Rate | Credit Facility              
Debt Instrument [Line Items]              
Base rate on debt         0.125%    
Bank Credit Facility | Minimum | LIBOR Rate              
Debt Instrument [Line Items]              
Base rate on debt 1.25%   1.25%        
Bank Credit Facility | Minimum | LIBOR Rate | Credit Facility              
Debt Instrument [Line Items]              
Base rate on debt         1.125%    
Bank Credit Facility | Maximum              
Debt Instrument [Line Items]              
Annual rate of commitment fee paid on the undrawn balance     0.375%        
Bank Credit Facility | Maximum | Credit Facility              
Debt Instrument [Line Items]              
Annual rate of commitment fee paid on the undrawn balance     0.30%        
Bank Credit Facility | Maximum | Alternate Base Rate              
Debt Instrument [Line Items]              
Base rate on debt 1.25%   1.25%        
Bank Credit Facility | Maximum | Alternate Base Rate | Credit Facility              
Debt Instrument [Line Items]              
Base rate on debt         0.75%    
Bank Credit Facility | Maximum | LIBOR Rate              
Debt Instrument [Line Items]              
Base rate on debt 2.25%   2.25%        
Bank Credit Facility | Maximum | LIBOR Rate | Credit Facility              
Debt Instrument [Line Items]              
Base rate on debt         1.75%