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Long-Term Debt and Financing Arrangements - Additional Information (Detail) - USD ($)
1 Months Ended 6 Months Ended
Jul. 01, 2017
Jun. 30, 2020
Jun. 30, 2020
Mar. 31, 2020
Dec. 31, 2019
Standby Letters of Credit [Member]          
Line Of Credit Facility [Line Items]          
Outstanding letters of credit   $ 32,600,000 $ 32,600,000    
Letters of credit expiration, year     2020    
Revolving Line of Credit Facility [Member] | Bank Revolving Line of Credit [Member]          
Line Of Credit Facility [Line Items]          
Unused and available borrowings under bank revolving line of credit   317,400,000 $ 317,400,000   $ 318,500,000
Credit Agreement [Member]          
Line Of Credit Facility [Line Items]          
Credit agreement, maximum borrowing capacity $ 350,000,000        
Credit agreement, matures Jul. 01, 2022        
Borrowings under credit agreement       $ 100,000,000  
Credit agreement, repaid   $ 100,000,000