Quarterly report pursuant to Section 13 or 15(d)

Borrowings - Additional Information (Details)

v3.10.0.1
Borrowings - Additional Information (Details)
Oct. 07, 2018
USD ($)
Dec. 31, 2017
USD ($)
Apr. 13, 2017
Jun. 30, 2016
USD ($)
Borrowings        
Loan origination costs $ 1,800,000 $ 2,400,000    
Credit Facility | Revolving credit facility        
Borrowings        
Amounts outstanding   265,500,000    
Credit Facility | Letter of credit        
Borrowings        
Amounts outstanding   $ 7,600,000    
Credit Facility | Line of credit        
Borrowings        
Amounts outstanding 220,000,000      
Credit Facility | Revolving credit facility        
Borrowings        
Maximum borrowing capacity       $ 400,000,000
Additional pricing tiers, lease adjusted leverage ratio threshold     4.75  
Credit Facility | Revolving credit facility | Through October 1, 2017        
Borrowings        
Covenant compliance, lease adjusted leverage ratio     5.25  
Credit Facility | Revolving credit facility | October 2, 2017 through July 15, 2018        
Borrowings        
Covenant compliance, lease adjusted leverage ratio     5.0  
Credit Facility | Revolving credit facility | July 16, 2018 and Thereafter        
Borrowings        
Covenant compliance, lease adjusted leverage ratio     4.75  
Credit Facility | Letter of credit | Line of credit        
Borrowings        
Maximum borrowing capacity       25,000,000
Amounts outstanding $ 7,600,000      
Credit Facility | Swingline loans | Line of credit        
Borrowings        
Maximum borrowing capacity       $ 15,000,000