Employee and Retiree Benefit Plans - Weighted Average Asset Allocation for Funded Pension Benefit Plans (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Retirement plan assets		$ 547,484	$ 487,094
Weighted average asset allocation		100.00%	100.00%
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocation		54.90%	56.00%
Defined Benefit Plan, Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocation		26.20%	42.20%
Other
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocation		17.30%
Defined Benefit Plan, Cash and Equivalents
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocation		1.60%	1.80%
Domestic Plan | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocation	54.00%
Domestic Plan | Defined Benefit Plan, Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocation	27.80%
Domestic Plan | Other
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocation	16.90%
Domestic Plan | Defined Benefit Plan, Cash and Equivalents
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocation	1.30%
Domestic Plan | Minimum | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target allocations of plan assets	40.00%
Domestic Plan | Minimum | Defined Benefit Plan, Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Target allocations of plan assets	25.00%
Domestic Plan | Minimum | Other
Defined Benefit Plan Disclosure [Line Items]
Target allocations of plan assets	0.00%
Domestic Plan | Minimum | Defined Benefit Plan, Cash and Equivalents
Defined Benefit Plan Disclosure [Line Items]
Target allocations of plan assets	0.00%
Domestic Plan | Maximum | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target allocations of plan assets	70.00%
Domestic Plan | Maximum | Defined Benefit Plan, Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Target allocations of plan assets	60.00%
Domestic Plan | Maximum | Other
Defined Benefit Plan Disclosure [Line Items]
Target allocations of plan assets	20.00%
Domestic Plan | Maximum | Defined Benefit Plan, Cash and Equivalents
Defined Benefit Plan Disclosure [Line Items]
Target allocations of plan assets	15.00%
Canadian Plan | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocation	34.50%
Canadian Plan | Defined Benefit Plan, Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocation	63.50%
Canadian Plan | Other
Defined Benefit Plan Disclosure [Line Items]
Target allocations of plan assets	0.00%
Weighted average asset allocation	0.00%
Canadian Plan | Defined Benefit Plan, Cash and Equivalents
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocation	2.00%
Canadian Plan | Minimum | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target allocations of plan assets	28.00%
Canadian Plan | Minimum | Defined Benefit Plan, Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Target allocations of plan assets	60.00%
Canadian Plan | Minimum | Defined Benefit Plan, Cash and Equivalents
Defined Benefit Plan Disclosure [Line Items]
Target allocations of plan assets	0.00%
Canadian Plan | Maximum | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target allocations of plan assets	38.00%
Canadian Plan | Maximum | Defined Benefit Plan, Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Target allocations of plan assets	70.00%
Canadian Plan | Maximum | Defined Benefit Plan, Cash and Equivalents
Defined Benefit Plan Disclosure [Line Items]
Target allocations of plan assets	10.00%
U.K. Plan | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocation	59.20%
U.K. Plan | Defined Benefit Plan, Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocation	18.40%
U.K. Plan | Other
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocation	20.20%
U.K. Plan | Defined Benefit Plan, Cash and Equivalents
Defined Benefit Plan Disclosure [Line Items]
Weighted average asset allocation	2.20%