Basis of Preparation - Narratives (Details) $ / shares in Units, shares in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2021 USD ($) location $ / shares	Jun. 30, 2020 USD ($) $ / shares	Mar. 31, 2020 USD ($) $ / shares shares	Jun. 30, 2021 USD ($) location $ / shares	Jun. 30, 2020 USD ($) $ / shares	Jan. 01, 2021 USD ($)	Dec. 31, 2020 USD ($)	Mar. 11, 2020 USD ($)	Nov. 06, 2017 USD ($)
Debt and Equity Securities, FV-NI
Number of locations (location) | location		25			25
Shares authorized for repurchase								$ 75,000,000	$ 75,000,000
Shares repurchased during the period (shares) | shares				760
Weighted average share price of shares repurchased (per share) | $ / shares				$ 25.40
Common stock repurchases	[1]			$ 19,300,000
Interest expense, net		$ 2,200,000	$ 7,600,000		$ 4,200,000	$ 14,800,000
Income from continuing operations		$ 6,500,000	$ 13,800,000		$ 32,100,000	$ 15,900,000
Income from continuing operations basic (usd per share) | $ / shares		$ 0.18	$ 0.39		$ 0.90	$ 0.45
Income from continuing operations diluted (usd per share) | $ / shares		$ 0.16	$ 0.39		$ 0.79	$ 0.45
Scenario, Plan
Debt and Equity Securities, FV-NI
Interest expense, net		$ 2,100,000			$ 4,100,000
Income from continuing operations		$ 4,900,000			$ 28,900,000
Income from continuing operations basic (usd per share) | $ / shares		$ 0.04			$ 0.09
Income from continuing operations diluted (usd per share) | $ / shares		$ 0.04			$ 0.08
Convertible Notes, due 2024 | Convertible Debt
Debt and Equity Securities, FV-NI
Principal amount		$ 258,800,000	$ 258,800,000		$ 258,800,000	$ 258,800,000		258,800,000		$ 258,800,000
Interest expense, net		700,000	$ 700,000		1,300,000	$ 1,300,000
Unamortized discount		0			0			34,800,000
Unamortized debt issuance costs		$ 3,300,000			$ 3,300,000		$ 3,900,000	$ 3,100,000

[1] Includes $19.3 in shares repurchased through our share repurchase program. On March 11, 2021, the share repurchase program expired with no further repurchases. Refer to Note 1, “Basis of Preparation” for further information.