Pension and Other Postretirement Benefits - Fair Value Hierarchy - Assets (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	$ 222,399,000	$ 93,273,000
Fair Value of Plan Assets measured at NAV	93,250,000	50,968,000
Fair Value of Plan Assets	315,649,000	144,241,000
Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1,952,000	659,000
Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	108,773,000	10,359,000
Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	111,674,000	82,255,000	$ 84,520,000
Insurance Contract [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	92,657,000
Fair Value of Plan Assets	92,657,000	79,873,000	82,092,000
Real Estate Fund [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	9,581,000	2,382,000	2,428,000
Other-alternative investments [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	9,436,000	0	$ 0
Domestic plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	69,146,000	450,000
Fair Value of Plan Assets	120,550,000	49,415,000
Domestic plan [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	450,000	450,000
Domestic plan [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	64,636,000	0
Domestic plan [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	4,060,000	0
Domestic plan [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	450,000	450,000
Domestic plan [Member] | Cash and Cash Equivalents [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	450,000	450,000
Domestic plan [Member] | Cash and Cash Equivalents [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0	0
Domestic plan [Member] | Cash and Cash Equivalents [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0	0
Domestic plan [Member] | Pooled Separate Accounts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	64,636,000
Domestic plan [Member] | Pooled Separate Accounts [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0
Domestic plan [Member] | Pooled Separate Accounts [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	64,636,000
Domestic plan [Member] | Pooled Separate Accounts [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0
Domestic plan [Member] | Real Estate Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	4,060,000
Domestic plan [Member] | Real Estate Fund [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0
Domestic plan [Member] | Real Estate Fund [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0
Domestic plan [Member] | Real Estate Fund [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	4,060,000
Domestic plan [Member] | Commingled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets measured at NAV	51,404,000	48,965,000
Foreign [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	153,253,000	92,823,000
Fair Value of Plan Assets measured at NAV		2,003,000
Fair Value of Plan Assets	195,099,000	94,826,000
Foreign [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	1,502,000	209,000
Foreign [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	44,137,000	10,359,000
Foreign [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	107,614,000	82,255,000
Foreign [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	1,502,000	209,000
Foreign [Member] | Cash and Cash Equivalents [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	1,502,000	209,000
Foreign [Member] | Cash and Cash Equivalents [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0	0
Foreign [Member] | Cash and Cash Equivalents [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0	0
Foreign [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	3,021,000	2,658,000
Foreign [Member] | Fixed Income Funds [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0	0
Foreign [Member] | Fixed Income Funds [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	3,021,000	2,658,000
Foreign [Member] | Fixed Income Funds [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0	0
Foreign [Member] | Domestic And Foreign Government Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	32,512,000
Foreign [Member] | Domestic And Foreign Government Debt Securities [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0
Foreign [Member] | Domestic And Foreign Government Debt Securities [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	32,512,000
Foreign [Member] | Domestic And Foreign Government Debt Securities [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0
Foreign [Member] | Insurance Contract [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	92,657,000	79,873,000
Foreign [Member] | Insurance Contract [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0	0
Foreign [Member] | Insurance Contract [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0	0
Foreign [Member] | Insurance Contract [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	92,657,000	79,873,000
Foreign [Member] | Equity Funds Diversified [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	8,604,000	7,701,000
Foreign [Member] | Equity Funds Diversified [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0	0
Foreign [Member] | Equity Funds Diversified [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	8,604,000	7,701,000
Foreign [Member] | Equity Funds Diversified [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0	0
Foreign [Member] | Real Estate Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	5,521,000	2,382,000
Foreign [Member] | Real Estate Fund [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0	0
Foreign [Member] | Real Estate Fund [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0	0
Foreign [Member] | Real Estate Fund [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	5,521,000	2,382,000
Foreign [Member] | Commingled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets measured at NAV	2,037,000	$ 2,003,000
Foreign [Member] | Diversified investment fund - registered investment companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets measured at NAV	39,809,000
Foreign [Member] | Other-alternative investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	9,436,000
Foreign [Member] | Other-alternative investments [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0
Foreign [Member] | Other-alternative investments [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0
Foreign [Member] | Other-alternative investments [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	$ 9,436,000