XML 48 R38.htm IDEA: XBRL DOCUMENT v3.10.0.1
Bank Credit Arrangements - Additional Information (Detail) - USD ($)
3 Months Ended
Dec. 31, 2018
Sep. 30, 2018
Mar. 22, 2016
Debt Instrument [Line Items]      
Notional balance $ 60,000,000    
Interest rate swap description (i) notional reduction amounts and dates; (ii) LIBOR settlement rates; (iii) rate reset dates; and (iv) term/maturity.    
Interest rate swap asset $ 1,145,000 $ 1,722,000  
Bank credit arrangement, fixed interest rate percentage 2.76%    
Credit facility with a commercial bank $ 30,000,000    
Expiration date of credit facility Mar. 31, 2021    
Borrowings outstanding under credit facility $ 0 $ 0  
Cash compensating balance 1,000,000    
Magellan [Member]      
Debt Instrument [Line Items]      
2019 4,125,000    
2020 6,000,000    
2021 $ 39,000,000    
Five - Year Term Loan [Member] | Magellan [Member]      
Debt Instrument [Line Items]      
Term loan     $ 60,000,000