Pension and Postretirement Benefits - Narrative (Details) - USD ($)		1 Months Ended			6 Months Ended
	Feb. 08, 2019	Mar. 31, 2019	Feb. 07, 2019	Jan. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Postemployment Benefits [Abstract]
Pension settlement payments		$ 105,900,000	$ 190,500,000	$ 190,500,000	$ 0	$ 105,900,000
Pension settlement charge			$ 85,800,000		$ 0	$ 0
Unrecognized actuarial gains (losses)	$ 0