Quarterly Financial Information (unaudited) (Parenthetical) (Details) - USD ($) $ in Thousands	3 Months Ended											12 Months Ended
	Dec. 31, 2020		Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019		Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	[3]	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income from continuing operations	$ 14,642	[1]	$ 16,750	$ 17,202	$ 8,275	$ 17,853	[2]	$ 16,688	$ 10,837	$ (161)		$ 56,869	$ 45,217	$ 97,902
Selling, General and Administrative Expenses
Acquisition and integration costs	600
Business acquisition, integration and project Costs						$ 4,300							$ 4,300
Strategic Project Costs | Selling, General and Administrative Expenses
Income from continuing operations	2,300
CEO Transition Costs | Selling, General and Administrative Expenses
Income from continuing operations	$ 1,000

[1] Income from continuing operations for the fourth quarter of 2020 includes strategic project costs, CEO transition costs, and acquisition and integration costs of $2.3 million, $1.0 million, and $0.6 million, respectively, each of which were primarily recorded to selling, general, and administrative expenses.

[2] Income from continuing operations for the fourth quarter of 2019 includes acquisition, integration, and project costs totaling $4.3 million, which were primarily recorded to selling, general, and administrative expenses.

[3] The impact of potentially dilutive securities for the three months ended March 31, 2019 was not considered because the impact on continuing operations would be anti-dilutive.