Borrowing Arrangements - Narrative (Details)		1 Months Ended	3 Months Ended
	May 06, 2020 USD ($)	May 31, 2019 USD ($)	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020 USD ($) $ / shares	Dec. 31, 2019 USD ($)	Mar. 31, 2019	Nov. 30, 2018 USD ($)
Debt Instrument [Line Items]
Long-term borrowings						$ 381,700,000	$ 369,000,000.0
Approximate redumption value of Convertible Debentures						$ 1,100,000
Restated Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity									$ 550,000,000.0
Percentage principal installments						1.25%
Senior credit facility, net of discount
Debt Instrument [Line Items]
Long-term borrowings						$ 356,800,000	$ 345,900,000
Weighted average interest rate						2.70%		4.30%
Senior credit facility, net of discount | Restated Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity									325,000,000.0
Letters of credit outstanding						$ 52,500,000
Long-term borrowings						$ 381,700,000
Senior credit facility, net of discount | Senior Credit Facility
Debt Instrument [Line Items]
Weighted average interest rate						2.60%		3.90%
Letter of credit facility | Restated Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity									100,000,000.0
Term loan facility | Restated Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity									$ 225,000,000.0
Convertible Subordinated Debt
Debt Instrument [Line Items]
Redemption price upon stated maturity (in dollars per share) | $ / shares						$ 19.18
LIBOR Loans | Senior credit facility, net of discount | Restated Credit Agreement
Debt Instrument [Line Items]
Period of total debt to EBITDA ratio						12 months
Base rate loans | Senior credit facility, net of discount | Restated Credit Agreement | Federal funds
Debt Instrument [Line Items]
Interest rate margin on variable rate basis						0.50%
Base rate loans | Senior credit facility, net of discount | Restated Credit Agreement | LIBOR
Debt Instrument [Line Items]
Floor interest rate						0.00%
Interest rate margin on variable rate basis						1.00%
Maximum | Senior credit facility, net of discount | Restated Credit Agreement
Debt Instrument [Line Items]
Total debt to EBITDA ratio that is required to be maintained						4.25
Credit Agreement Total Debt to EBITDA Ratio that is Required to be Maintained Step Down						4.00
Minimum | Senior credit facility, net of discount | Restated Credit Agreement
Debt Instrument [Line Items]
Fixed charge coverage ratio that is required to be maintained						3.50
Interest rate collars
Debt Instrument [Line Items]
Interest rate collar, term		3 years
Notional amount		$ 222,300,000
Derivative, cap interest rate						2.50%
Subsequent event | Senior credit facility, net of discount | Restated Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 370,000,000.0
Liquidity test minimum	50,000,000.0
Increase to borrowing capacity	45,000,000.0
Fees and other closing cost	$ 1,600,000
Subsequent event | Base rate loans | Senior credit facility, net of discount | Restated Credit Agreement | LIBOR
Debt Instrument [Line Items]
Floor interest rate	1.00%
Interest rate margin on variable rate basis	2.75%
Subsequent event | Revolving Credit Facility | Senior credit facility, net of discount | Restated Credit Agreement
Debt Instrument [Line Items]
Interest rate	0.375%
Forecast | Restated Credit Agreement
Debt Instrument [Line Items]
Percentage principal installments					1.875%
Forecast | Maximum | Senior credit facility, net of discount | Restated Credit Agreement
Debt Instrument [Line Items]
Total debt to EBITDA ratio that is required to be maintained			5.50
Forecast | Minimum | Senior credit facility, net of discount | Restated Credit Agreement
Debt Instrument [Line Items]
Fixed charge coverage ratio that is required to be maintained				2.75