Debt (Debt Covenants and Compliance) (Details)	9 Months Ended
	Sep. 30, 2020 USD ($)	Oct. 01, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019 USD ($)
Debt Instrument [Line Items]
Cash and cash equivalents	$ 92,900,000							$ 78,700,000
Senior secured leverage ratio to consolidated EBITDA	2.39
Ratio of interest coverage	4.88
Actual total leverage ratio	3.18
Financing Agreement Senior Secured Credit Facility
Debt Instrument [Line Items]
Maximum annual dividend payment	$ 60,000,000.0
Maximum
Debt Instrument [Line Items]
Senior secured leverage ratio to consolidated EBITDA	3.50
Maximum | Financing Agreement Senior Secured Credit Facility
Debt Instrument [Line Items]
Total leverage ratio	2.75
Senior secured leverage ratio	3.00
Total leverage ratio on unsecured debt	3.50
Minimum
Debt Instrument [Line Items]
Ratio of interest coverage, covenant compliance	3.00
Senior Unsecured Notes
Debt Instrument [Line Items]
Interest rate, percentage	7.00%
Senior Secured Credit Facility
Debt Instrument [Line Items]
Cash and cash equivalents	$ 75,000,000.0
Total leverage ratio, covenant compliance	4.25						4.25
Effective total leverage ratio, covenant compliance	3.23
Senior Secured Credit Facility | Subsequent Event
Debt Instrument [Line Items]
Total leverage ratio, covenant compliance			4.125	4.25	4.50	4.50
Senior Secured Credit Facility | Maximum | Subsequent Event
Debt Instrument [Line Items]
Total leverage ratio, covenant compliance		3.75