v3.20.4
Debt - Additional Information (Details) - USD ($)
1 Months Ended 12 Months Ended
Nov. 18, 2019
May 03, 2019
Mar. 31, 2020
Dec. 31, 2020
Dec. 31, 2019
Debt Instrument [Line Items]          
Letters of credit outstanding       $ 30,900,000 $ 31,800,000
Credit Agreement          
Debt Instrument [Line Items]          
Interest expense       2,600,000 400,000
Credit Agreement | Morgan Stanley Senior Funding, Inc | Minimum          
Debt Instrument [Line Items]          
Adjusted quick ratio   1.00%      
Credit Agreement | Morgan Stanley Senior Funding, Inc | Revolving Credit Facility          
Debt Instrument [Line Items]          
Debt instrument term, years   4 years      
Maximum borrowing capacity   $ 100,000,000.0      
Amount borrowed under debt facility     $ 69,300,000    
Credit facility expiration and maturity month and year   2023-02      
Letters of credit outstanding       $ 30,800,000 $ 30,700,000
Credit Agreement | Morgan Stanley Senior Funding, Inc | Revolving Credit Facility | Adjusted One-Month LIBOR          
Debt Instrument [Line Items]          
Debt instrument, applicable margin on variable rate     1.75%    
Credit Agreement | Morgan Stanley Senior Funding, Inc | Term Loan A Facility          
Debt Instrument [Line Items]          
Debt instrument term, years   4 years      
Maximum borrowing capacity   $ 100,000,000.0      
Amount borrowed under debt facility $ 100,000,000.0        
Debt instrument, amortization description       Loans under the Term Loan A Facility amortize in equal quarterly installments beginning on March 31, 2020, in an aggregate annual amount equal to (i) on or prior to December 31, 2021, 1.25% of the drawn principal amount of the Term Loan Facility or $1.25 million and (ii) thereafter, 2.50% of the drawn principal amount of the Term Loan Facility or $2.5 million, with the remaining balance payable on the maturity date of the Term Loan A Facility in February 2023.  
Debt instrument maturity month and year   2023-02      
Credit Agreement | Morgan Stanley Senior Funding, Inc | Term Loan A Facility | On or Prior to December 31, 2021          
Debt Instrument [Line Items]          
Percentage of amortization on drawn principal amount   1.25%      
Amortization, aggregate principal amount   $ 1,250,000      
Credit Agreement | Morgan Stanley Senior Funding, Inc | Term Loan A Facility | Thereafter December 31, 2021          
Debt Instrument [Line Items]          
Percentage of amortization on drawn principal amount   2.50%      
Amortization, aggregate principal amount   $ 2,500,000      
Credit Agreement | Morgan Stanley Senior Funding, Inc | Term Loan A Facility | Adjusted One-Month LIBOR          
Debt Instrument [Line Items]          
Debt instrument, applicable margin on variable rate 1.75%        
Credit Agreement | Morgan Stanley Senior Funding, Inc | Uncommitted Incremental Facility          
Debt Instrument [Line Items]          
Maximum borrowing capacity   $ 50,000,000.0      
Debt to company's EBITDA, description       1.0x of the Company’s EBITDA for the most recently completed four fiscal quarter period  
Credit Agreement | Morgan Stanley Senior Funding, Inc | Uncommitted Incremental Facility | Maximum          
Debt Instrument [Line Items]          
Secured leverage ratio   1.50%