Debt and Credit Agreements - Changes in the Carrying Amount of Debt Obligations (Details) - USD ($) $ in Thousands		12 Months Ended
	Nov. 15, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Long-term Debt [Roll Forward]
Repayments		$ (200,000)	$ (90,000)	$ (77,000)
Prior Term Loan Facility | Line of Credit
Long-term Debt [Roll Forward]
Balance transfer	$ (80,000)
Current Revolving Credit Facility | Line of Credit
Long-term Debt [Roll Forward]
Balance		50,000
Proceeds		150,000
Repayments		(200,000)
Balance transfer	$ 80,000
Balance		$ 0	$ 50,000