DEBT - Additional Information (Detail) - USD ($)		1 Months Ended	3 Months Ended	6 Months Ended
	Apr. 13, 2018	Mar. 31, 2015	Sep. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Sep. 30, 2017
Line of Credit Facility [Line Items]
Letters of Credit Outstanding, Amount			$ 68,400,000		$ 68,400,000	$ 68,500,000
Line Of Credit Facility Unused Capacity Commitment Fee Percentage			0.40%
Letter of Credit Annual Fee Percentage			2.25%
Line of Credit Facility, Initiation Date	Apr. 13, 2018	Mar. 31, 2015
Debt, Weighted Average Interest Rate						3.24%
Line of Credit Facility, Remaining Borrowing Capacity			$ 231,600,000
Debt Instrument, Description of Variable Rate Basis			base rate plus 2%
Long-term Debt			$ 292,579,000		$ 293,073,000	$ 135,000,000
Line of Credit Facility, Increase (Decrease), Net	$ 250,000,000
Debt Issuance Costs, Gross			$ 9,900,000
Term B Loan [Member]
Line of Credit Facility [Line Items]
Debt, Weighted Average Interest Rate			5.24%
Debt Instrument, Maturity Date	Apr. 13, 2025
Debt Instrument, Face Amount	$ 300,000,000
Debt Instrument, Periodic Payment, Principal	750,000
Debt Issuance Costs, Gross	7,100,000
Eurocurrency Rate [Member] | Term B Loan [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Description of Variable Rate Basis			LIBOR-equivalent rate plus 3%
Base Rate [Member] | Term B Loan [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate			2.00%
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 300,000,000
Line of Credit Facility, Expiration Date	Apr. 13, 2023	Mar. 31, 2020
Foreign Currency Borrowing Capacity	$ 200,000,000	$ 400,000,000
Long-term Debt						$ 135,000,000
Debt Issuance Costs, Gross	2,700,000
Revolving Credit Facility [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate During Period			1.75%
Revolving Credit Facility [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate During Period			2.75%
Revolving Credit Facility [Member] | Prime Rate [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate During Period			0.75%
Revolving Credit Facility [Member] | Prime Rate [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate During Period			1.75%
Letter of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 100,000,000	$ 100,000,000
Letter Of Credit Title IV Disbursement, Amount				$ 68,400,000