Derivative Financial Instruments (Schedule of Volume of Derivative Activity) (Detail)	Jun. 30, 2019 USD ($)	[1]
Interest Rate Swap Current [Member]
Derivative [Line Items]
Interest rate	$ 0
Interest Rate Swap Noncurrent[Member]
Derivative [Line Items]
Interest rate	$ 71,400,000

[1] Maturity is determined based on final settlement period.