Pension and Other Postretirement Benefits - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined contribution expense	$ 12,100	$ 11,800	$ 11,400
Accumulated benefit obligation	$ 456,900	407,000
Target asset allocation for the investment of the assets in fixed income securities minimum	50.00%
Target asset allocation for the investment of the assets in fixed income securities maximum	75.00%
Target asset allocation for the investment of the assets in equity securities minimum	25.00%
Target asset allocation for the investment of the assets in equity securities maximum	50.00%
Minimum
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation for the investment of the assets in fixed income securities	30.00%
Target asset allocation for the investment of the assets in equity securities	50.00%
Maximum
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation for the investment of the assets in fixed income securities	50.00%
Target asset allocation for the investment of the assets in equity securities	70.00%
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension plans with projected benefit obligation in excess of plan assets, projected benefit obligation	$ 293,700	363,100
Pension plans with projected benefit obligation in excess of plan assets, accumulated benefit obligation	400,400	357,400
Pension plans with projected benefit obligation in excess of plan assets, fair value of plan assets	404,900	256,900
Settlement loss (gain)	7	1,300
Anticipated pension and other postretirement plans contributions, next fiscal year	6,100
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Other postretirement plans with accumulated benefit obligation in excess of plan assets, accumulated benefit obligation	29,500	26,100
Other postretirement plans with accumulated benefit obligation in excess of plan assets, fair value of plan assets	0	$ 0
Settlement loss (gain)	0
Anticipated pension and other postretirement plans contributions, next fiscal year	$ 1,400