Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Restricted stock units vested but common shares not distributed.

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Equity-Based Compensation Plans - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restricted Stock and Stock Unit
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation cost share based awards	$ 2.9	$ 3.6	$ 6.2
Restricted stock units vested but common shares not distributed (in shares)	580,000	500,000	660,000
Intrinsic value, outstanding	$ 7.0
Unrecognized compensation expense	$ 1.6
Period of recognition	8 months 12 days
Vested in Period, Fair Value	$ 4.5	$ 7.1	$ 5.0
2020 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for issuance (in shares)	3,000,000.0
2019 Incentive and Equity Award Plan \| Key Management Personnel
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for issuance (in shares)	2,500,000
Amended and Restated 2011 Incentive and Equity Award Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for issuance (in shares)	5,000,000.0
2011 and 2019 Incentive and Equity Award Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for issuance (in shares)	2,800,000
Equity award plan. vesting rights	According to the plan provisions, the stock units provide the holders the right to receive one share of our Common Stock upon vesting (and distribution) of one stock unit.
2011 and 2019 Incentive and Equity Award Plan \| Performance Based Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period	30 days
Compensation cost share based awards	$ 1.8	$ 2.6