Financing Arrangements - 2026 Senior Notes - Additional Information (Detail) - USD ($)					3 Months Ended			6 Months Ended				12 Months Ended
		Oct. 28, 2019	Oct. 09, 2019	Jan. 02, 2018	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2021		Mar. 31, 2020		Sep. 30, 2020	Oct. 01, 2015
Debt Instrument [Line Items]
Loss on debt extinguishment					$ 9,500,000	$ 0		$ 9,500,000	[1]	$ 14,700,000	[1]
Payments of debt issuance costs				$ 65,300,000				$ 0	[1]	$ 3,700,000	[1]
Senior Notes, Matures October 2023 [Member]
Debt Instrument [Line Items]
Debt instrument, aggregate principal amount			$ 300,000,000.0
Debt instrument interest rate			4.50%										6.38%
Debt instrument, issue price percentage			100.00%
Debt instrument maturity date			Nov. 15, 2026
Debt instrument, interest payable commencement date			May 15, 2020
Redemption of senior debt		$ 300,000,000.0
Debt redemption price percentage of principal amount		103.188%
Unamortized debt issuance costs		$ 5,100,000
Senior Notes, Matures October 2023 [Member]
Debt Instrument [Line Items]
Debt instrument interest rate					4.50%	4.50%		4.50%		4.50%		4.50%
Debt instrument maturity date								Nov. 15, 2026		Nov. 15, 2026		Nov. 15, 2026
Redemption of senior debt		$ 300,000,000.0
Debt redemption price percentage of principal amount		103.188%
Debt instrument, redemption description								On October 28, 2019, the Company used the net proceeds from the offering, together with cash on hand and available borrowings under the 2023 ABL (as defined below), to redeem all $300.0 million aggregate principal amount outstanding of the 2023 Senior Notes (as defined below) at a redemption price of 103.188%
Payments of debt issuance costs			$ 4,700,000
Unamortized debt issuance costs					$ 3,800,000			$ 3,800,000
Senior Notes Payable	[2]				$ 296,200,000	$ 295,800,000		$ 296,200,000		$ 295,800,000		$ 295,900,000
Refinancing the Existing 2023 Senior Notes with Issuance of 2026 Senior Notes [Member]
Debt Instrument [Line Items]
Loss on debt extinguishment							$ 14,700,000

[1] Unless otherwise noted, amounts include both continuing and discontinued operations.

[2] Interest rate of 4.50% for all periods presented.