Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt - Additional Information (Details)

v3.20.1
Long-Term Debt - Additional Information (Details) - USD ($)
3 Months Ended 12 Months Ended
Mar. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Debt Instrument [Line Items]      
Senior notes $ 45,000,000 $ 45,000,000  
Fixed interest rate 4.79%    
Debt instrument, due date Jan. 03, 2021    
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage 0.10%    
Letter of Credit Fee in Percentage 1.00%    
Letters of Credit Outstanding, Amount $ 45,700,000 48,900,000  
Minimum [Member]      
Debt Instrument [Line Items]      
Interest Rate Spread added to Rate 0.00%    
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage 0.10%    
Maximum [Member]      
Debt Instrument [Line Items]      
Interest Rate Spread added to Rate 0.375%    
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage 0.175%    
London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]      
Debt Instrument [Line Items]      
Interest Rate Spread added to Rate 1.00%    
London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]      
Debt Instrument [Line Items]      
Interest Rate Spread added to Rate 1.375%    
2019 Credit Agreement [Member]      
Debt Instrument [Line Items]      
Original borrowing capacity $ 250,000,000.0    
Line of Credit Facility Accordion 150,000,000.0    
Line of Credit Facility, Maximum Borrowing Capacity 400,000,000.0    
Letter of Credit [Member]      
Debt Instrument [Line Items]      
Line of Credit Facility, Capacity Available for Specific Purpose Other than for Trade Purchases 100,000,000.0    
Prior Credit Agreement [Member]      
Debt Instrument [Line Items]      
Line of Credit Facility, Maximum Borrowing Capacity   $ 300,000,000.0  
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage   0.125% 0.125%
Letter of Credit Fee in Percentage   1.00% 1.00%
Unsecured Senior Note Due January 3, 2021 [Member]      
Debt Instrument [Line Items]      
Scheduled principal payment $ 45,000,000.0