Long-term Debt - Narrative (Details)			3 Months Ended			6 Months Ended	9 Months Ended		13 Months Ended
	Jun. 17, 2020 USD ($)	Jan. 30, 2018 USD ($) day $ / shares	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Jun. 16, 2020	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Oct. 01, 2020 USD ($)	Jan. 31, 2018 USD ($)	Jan. 12, 2018
Debt Instrument [Line Items]
Repayments of convertible debt							$ 20,078,000	$ 858,000
Gain on extinguishment of debt							$ 10,721,000	$ 0
Unsecured Debt
Debt Instrument [Line Items]
Stated interest rate												2.50%
Debt instrument, face amount											$ 25,000,000.0
1.5% Convertible Unsecured Senior Notes Due February 2023
Debt Instrument [Line Items]
Stated interest rate			1.50%		1.50%		1.50%	1.50%	1.50%
1.5% Convertible Unsecured Senior Notes Due February 2023 | Convertible Debt
Debt Instrument [Line Items]
Stated interest rate			1.50%				1.50%		1.50%
Debt instrument, face amount		$ 200,000,000
Debt Instrument, principal amount repurchased			$ 17,200,000				$ 34,900,000		$ 42,600,000
Repayments of convertible debt			9,500,000				20,100,000		26,800,000
Debt instrument, liability component repurchased			15,400,000				30,800,000
Gain on extinguishment of debt			5,900,000				10,700,000
Effective interest rate percentage		6.00%
Interest expense			2,300,000		$ 2,600,000		7,200,000	$ 7,700,000
Interest expense, contractual interest			600,000		$ 800,000		2,000,000.0	$ 2,300,000
Conversion ratio		0.0222748
Conversion price (in dollars per share) | $ / shares		$ 44.89
Percentage of conversion price		130.00%
Threshold trading days | day		20
Threshold consecutive trading days | day		30
Threshold consecutive trading days, sale price per share | day		5
Measurement period | day		5
Percentage of sales price per share		98.00%
Amount of indebtedness in event of default		$ 40,000,000.0
Revolving Credit Facility Due January 2022
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 200,000,000.0	350,000,000.0
Covenant suspension period, borrowing availability	85.00%
Consolidated net book value of eligible receivables	70.00%
Consolidated net book value of eligible inventory	20.00%
Long-term line of credit			19,000,000.0				19,000,000.0		19,000,000.0
Letters of credit outstanding			31,200,000				$ 31,200,000		31,200,000
Remaining borrowing capacity										$ 83,800,000
Commitment fee percentage	0.50%
Unamortized debt issuance costs				$ 500,000
Minimum interest coverage ratio							3.0
Maximum senior secured leverage ratio							2.25
Maximum leverage ratio							3.75
Revolving Credit Facility Due January 2022 | UNITED STATES
Debt Instrument [Line Items]
Covenant maximum cash balance			$ 45,000,000.0				$ 45,000,000.0		$ 45,000,000.0
Revolving Credit Facility Due January 2022 | Minimum
Debt Instrument [Line Items]
Commitment fee percentage						0.25%
Revolving Credit Facility Due January 2022 | Maximum
Debt Instrument [Line Items]
Commitment fee percentage						0.50%
Revolving Credit Facility Due January 2022 | London Interbank Offered Rate (LIBOR) | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	2.50%					1.75%
Revolving Credit Facility Due January 2022 | London Interbank Offered Rate (LIBOR) | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	3.75%					3.00%
Revolving Credit Facility Due January 2022 | Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	1.50%					0.75%
Revolving Credit Facility Due January 2022 | Base Rate | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	2.75%					2.00%
Letter of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 50,000,000.0