XML 21 R35.htm IDEA: XBRL DOCUMENT v3.19.3
Debt - Additional Information (Details)
1 Months Ended 3 Months Ended 9 Months Ended
Oct. 31, 2014
USD ($)
Dec. 31, 2014
USD ($)
Sep. 30, 2019
USD ($)
derivative_instrument
Dec. 31, 2018
USD ($)
Feb. 28, 2018
USD ($)
Nov. 30, 2014
USD ($)
Line of Credit Facility [Line Items]            
Maximum capitalization ratio     55.00%      
Number of instruments held | derivative_instrument     2      
Interest rate swap principal     $ 200,000,000 $ 200,000,000    
Payments of financing costs   $ 3,000,000.0        
Minimum [Member]            
Line of Credit Facility [Line Items]            
Commitment fee percentage     0.125%      
Maximum [Member]            
Line of Credit Facility [Line Items]            
Commitment fee percentage     0.30%      
Senior Notes due 2024 [Member]            
Line of Credit Facility [Line Items]            
Senior notes     $ 500,000,000 $ 500,000,000   $ 500,000,000
Interest rate, stated percentage     4.65% 4.65%   4.65%
Interest rate swap principal     $ 200,000,000      
Payments of debt issuance costs   6,900,000        
Senior Notes due 2028 [Member]            
Line of Credit Facility [Line Items]            
Senior notes     $ 300,000,000 $ 300,000,000 $ 300,000,000  
Interest rate, stated percentage     6.00% 6.00% 6.00%  
Payments of debt issuance costs   $ 4,200,000        
Line of Credit [Member]            
Line of Credit Facility [Line Items]            
Maximum borrowing capacity $ 500,000,000          
Debt instrument, term 5 years          
Available additional borrowing capacity $ 300,000,000          
Face amount $ 300,000,000          
Percent of commitments affected by amendment         90.00%  
Line of Credit [Member] | October 25, 2021 [Member]            
Line of Credit Facility [Line Items]            
Maximum borrowing capacity         $ 500,000,000  
Line of Credit [Member] | January 25, 2023 [Member]            
Line of Credit Facility [Line Items]            
Maximum borrowing capacity         $ 450,000,000  
Credit Agreement [Member] | Applicable Margin [Member] | Minimum [Member] | Adjusted Base Rate Advances [Member]            
Line of Credit Facility [Line Items]            
Basis spread on variable rate     0.125%      
Credit Agreement [Member] | Applicable Margin [Member] | Minimum [Member] | Eurodollar Advances [Member]            
Line of Credit Facility [Line Items]            
Basis spread on variable rate     1.125%      
Credit Agreement [Member] | Applicable Margin [Member] | Maximum [Member] | Adjusted Base Rate Advances [Member]            
Line of Credit Facility [Line Items]            
Basis spread on variable rate     0.75%      
Credit Agreement [Member] | Applicable Margin [Member] | Maximum [Member] | Eurodollar Advances [Member]            
Line of Credit Facility [Line Items]            
Basis spread on variable rate     1.75%      
Credit Agreement [Member] | Adjusted Base Rate [Member] | Minimum [Member] | Adjusted Base Rate Advances [Member] | Federal Funds Rate [Member]            
Line of Credit Facility [Line Items]            
Basis spread on variable rate     0.50%      
Credit Agreement [Member] | Adjusted Base Rate [Member] | Minimum [Member] | Adjusted Base Rate Advances [Member] | Eurodollar Rate [Member]            
Line of Credit Facility [Line Items]            
Basis spread on variable rate     1.00%