Pension and Other Postretirement Benefits - Fair Value Hierarchy - Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 302,270	$ 315,649	$ 144,241
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	133,333	111,674	82,255
Insurance Contract [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	112,920
Fair Value of Plan Assets	112,920	92,657	79,873
Real Estate Fund [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	9,775	9,581	2,382
Other-alternative investments [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	10,638	9,436	0
Domestic plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	73,481	120,550	49,415
Foreign [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	228,789	195,099	$ 94,826
Fair Value Measurements Recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	302,270	315,649
Fair Value Measurements Recurring [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	253,493	222,399
Fair Value Measurements Recurring [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	634	1,952
Fair Value Measurements Recurring [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	119,526	108,773
Fair Value Measurements Recurring [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	133,333	111,674
Fair Value Measurements Recurring [Member] | Pension Assets At NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	48,777	93,250
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	73,481	69,146
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	450
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	69,385	64,636
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	4,096	4,060
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	450
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Cash and Cash Equivalents [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	450
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Cash and Cash Equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Cash and Cash Equivalents [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Pooled Separate Accounts [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	69,385	64,636
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Pooled Separate Accounts [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Pooled Separate Accounts [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	69,385	64,636
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Pooled Separate Accounts [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Real Estate Fund [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	4,096	4,060
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Real Estate Fund [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Real Estate Fund [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Real Estate Fund [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	4,096	4,060
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Commingled funds measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	51,404
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Pooled separate accounts measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Domestic plan [Member] | Pension Assets At NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	73,481	120,550
Fair Value Measurements Recurring [Member] | Foreign [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	180,012	153,253
Fair Value Measurements Recurring [Member] | Foreign [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	634	1,502
Fair Value Measurements Recurring [Member] | Foreign [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	50,141	44,137
Fair Value Measurements Recurring [Member] | Foreign [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	129,237	107,614
Fair Value Measurements Recurring [Member] | Foreign [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	634	1,502
Fair Value Measurements Recurring [Member] | Foreign [Member] | Cash and Cash Equivalents [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	634	1,502
Fair Value Measurements Recurring [Member] | Foreign [Member] | Cash and Cash Equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Foreign [Member] | Cash and Cash Equivalents [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Foreign [Member] | Insurance Contract [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	112,920	92,657
Fair Value Measurements Recurring [Member] | Foreign [Member] | Insurance Contract [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Foreign [Member] | Insurance Contract [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Foreign [Member] | Insurance Contract [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	112,920	92,657
Fair Value Measurements Recurring [Member] | Foreign [Member] | Diversified equity securities - registered investment companies [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	8,851	8,604
Fair Value Measurements Recurring [Member] | Foreign [Member] | Diversified equity securities - registered investment companies [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Foreign [Member] | Diversified equity securities - registered investment companies [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	8,851	8,604
Fair Value Measurements Recurring [Member] | Foreign [Member] | Diversified equity securities - registered investment companies [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Foreign [Member] | Fixed income - foreign registered investment companies [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	3,711	3,021
Fair Value Measurements Recurring [Member] | Foreign [Member] | Fixed income - foreign registered investment companies [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Foreign [Member] | Fixed income - foreign registered investment companies [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	3,711	3,021
Fair Value Measurements Recurring [Member] | Foreign [Member] | Fixed income - foreign registered investment companies [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Foreign [Member] | Fixed income government securities [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	37,579	32,512
Fair Value Measurements Recurring [Member] | Foreign [Member] | Fixed income government securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Foreign [Member] | Fixed income government securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	37,579	32,512
Fair Value Measurements Recurring [Member] | Foreign [Member] | Fixed income government securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Foreign [Member] | Real Estate Fund [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	5,679	5,521
Fair Value Measurements Recurring [Member] | Foreign [Member] | Real Estate Fund [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Foreign [Member] | Real Estate Fund [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Foreign [Member] | Real Estate Fund [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	5,679	5,521
Fair Value Measurements Recurring [Member] | Foreign [Member] | Other-alternative investments [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	10,638	9,436
Fair Value Measurements Recurring [Member] | Foreign [Member] | Other-alternative investments [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Foreign [Member] | Other-alternative investments [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Fair Value Measurements Recurring [Member] | Foreign [Member] | Other-alternative investments [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	10,638	9,436
Fair Value Measurements Recurring [Member] | Foreign [Member] | Commingled funds measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	2,368	2,037
Fair Value Measurements Recurring [Member] | Foreign [Member] | Diversified investment fund - registered investment companies measured at NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	46,409	39,809
Fair Value Measurements Recurring [Member] | Foreign [Member] | Pension Assets At NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 228,789	$ 195,099