Debt (Debt Covenant Compliance) (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)
Debt Instrument [Line Items]
Covenant compliance, leverage ratio	3.22
Covenant compliance senior secured leverage ratio	2.30
Interest coverage	4.52
Net leverage ratio	3.01
Maximum
Debt Instrument [Line Items]
Covenant compliance, leverage ratio	3.75
Covenant compliance senior secured leverage ratio	3.50
Minimum
Debt Instrument [Line Items]
Covenant compliance, interest coverage	3.00
Financing Agreement, April 2014
Debt Instrument [Line Items]
Covenant compliance maximum annual dividend payment	$ 120,000,000.0
Financing Agreement, April 2014 | Maximum
Debt Instrument [Line Items]
Covenant compliance total leverage ratio	2.75
Senior secured leverage ratio, payment restrictions on unsecured debt	3.00
Covenant compliance unsecured total leverage ratio	3.50