Pension and Other Postretirement Benefits - Fair Value Hierarchy - Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	$ 93,273	$ 98,456
Fair Value of Plan Assets measured at NAV	50,968	52,130
Fair Value of Plan Assets	144,241	150,586
Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	659	1,983
Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	10,359	11,953
Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	82,255	84,520	$ 74,819
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	79,873	82,092
Fair Value of Plan Assets	79,873	82,092	72,778
Real Estate Fund [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	2,382	2,428	$ 2,041
Domestic [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	450	1,957
Fair Value of Plan Assets	49,415	51,964
Domestic [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	450	1,957
Domestic [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 [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 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	450	449
Domestic [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	449
Domestic [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 [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 [Member] | Equity Securities Small Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0	1,508
Domestic [Member] | Equity Securities Small Cap [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	0	1,508
Domestic [Member] | Equity Securities Small Cap [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 [Member] | Equity Securities Small Cap [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 [Member] | Pooled Separate Accounts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets measured at NAV	0	1,480
Domestic [Member] | Commingled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets measured at NAV	48,965	48,527
Foreign [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	92,823	96,499
Fair Value of Plan Assets measured at NAV	2,003	2,123
Fair Value of Plan Assets	94,826	98,622
Foreign [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	209	26
Foreign [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	10,359	11,953
Foreign [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	82,255	84,520
Foreign [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	209	26
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	209	26
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	2,658	2,951
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	2,658	2,951
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] | Insurance Contract [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	79,873	82,092
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	79,873	82,092
Foreign [Member] | Equity Funds Diversified [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets excluding assets measured at NAV	7,701	9,002
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	7,701	9,002
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	2,382	2,428
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	2,382	2,428
Foreign [Member] | Commingled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets measured at NAV	$ 2,003	$ 2,123