Retirement Plans - Schedule of Fair Value of Plan Assets (Details) - USD ($) $ in Thousands		Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2016
United States [Member]
Fair value of plan assets		$ 43,100		$ 48,800	$ 49,800
Fair Value Measurements, Recurring [Member] | Insurance Contracts [Member] | International [Member]
Fair value of plan assets		16,000
Fair Value Measurements, Recurring [Member] | United States [Member]
Fair value of plan assets		43,100		48,800
Fair Value Measurements, Recurring [Member] | United States [Member] | Level 1 [Member]
Fair value of plan assets		5,200		1,100
Fair Value Measurements, Recurring [Member] | United States [Member] | Level 2 [Member]
Fair value of plan assets
Fair Value Measurements, Recurring [Member] | United States [Member] | Level 3 [Member]
Fair value of plan assets
Fair Value Measurements, Recurring [Member] | United States [Member] | Short-term Investments [Member] | Money Market Securities [Member]
Fair value of plan assets		5,200		500
Fair Value Measurements, Recurring [Member] | United States [Member] | Short-term Investments [Member] | Money Market Securities [Member] | Level 1 [Member]
Fair value of plan assets		5,200		500
Fair Value Measurements, Recurring [Member] | United States [Member] | Short-term Investments [Member] | Money Market Securities [Member] | Level 2 [Member]
Fair value of plan assets
Fair Value Measurements, Recurring [Member] | United States [Member] | Short-term Investments [Member] | Money Market Securities [Member] | Level 3 [Member]
Fair value of plan assets
Fair Value Measurements, Recurring [Member] | United States [Member] | Equity Securities [Member] | US Small Cap Core [Member]
Fair value of plan assets	[1]	1,000
Fair Value Measurements, Recurring [Member] | United States [Member] | Equity Securities [Member] | US Small Cap Core [Member] | Level 1 [Member]
Fair value of plan assets	[1]
Fair Value Measurements, Recurring [Member] | United States [Member] | Equity Securities [Member] | US Small Cap Core [Member] | Level 2 [Member]
Fair value of plan assets	[1]
Fair Value Measurements, Recurring [Member] | United States [Member] | Equity Securities [Member] | US Small Cap Core [Member] | Level 3 [Member]
Fair value of plan assets	[1]
Fair Value Measurements, Recurring [Member] | United States [Member] | Equity Securities [Member] | Large-cap Growth Funds [Member]
Fair value of plan assets		12,500	[1]	19,000
Fair Value Measurements, Recurring [Member] | United States [Member] | Equity Securities [Member] | Large-cap Growth Funds [Member] | Level 1 [Member]
Fair value of plan assets			[1]
Fair Value Measurements, Recurring [Member] | United States [Member] | Equity Securities [Member] | Large-cap Growth Funds [Member] | Level 2 [Member]
Fair value of plan assets			[1]
Fair Value Measurements, Recurring [Member] | United States [Member] | Equity Securities [Member] | Large-cap Growth Funds [Member] | Level 3 [Member]
Fair value of plan assets			[1]
Fair Value Measurements, Recurring [Member] | United States [Member] | Equity Securities [Member] | Emerging Markets [Member]
Fair value of plan assets	[1]	3,000
Fair Value Measurements, Recurring [Member] | United States [Member] | Equity Securities [Member] | Emerging Markets [Member] | Level 1 [Member]
Fair value of plan assets	[1]
Fair Value Measurements, Recurring [Member] | United States [Member] | Equity Securities [Member] | Emerging Markets [Member] | Level 2 [Member]
Fair value of plan assets	[1]
Fair Value Measurements, Recurring [Member] | United States [Member] | Equity Securities [Member] | Emerging Markets [Member] | Level 3 [Member]
Fair value of plan assets	[1]
Fair Value Measurements, Recurring [Member] | United States [Member] | Equity Securities [Member] | International Growth Fund [Member]
Fair value of plan assets		9,700	[1]	15,700
Fair Value Measurements, Recurring [Member] | United States [Member] | Equity Securities [Member] | International Growth Fund [Member] | Level 1 [Member]
Fair value of plan assets			[1]
Fair Value Measurements, Recurring [Member] | United States [Member] | Equity Securities [Member] | International Growth Fund [Member] | Level 2 [Member]
Fair value of plan assets			[1]
Fair Value Measurements, Recurring [Member] | United States [Member] | Equity Securities [Member] | International Growth Fund [Member] | Level 3 [Member]
Fair value of plan assets			[1]
Fair Value Measurements, Recurring [Member] | United States [Member] | Common Stocks [Member]
Fair value of plan assets			[1]	600
Fair Value Measurements, Recurring [Member] | United States [Member] | Common Stocks [Member] | Level 1 [Member]
Fair value of plan assets				600
Fair Value Measurements, Recurring [Member] | United States [Member] | Common Stocks [Member] | Level 2 [Member]
Fair value of plan assets
Fair Value Measurements, Recurring [Member] | United States [Member] | Common Stocks [Member] | Level 3 [Member]
Fair value of plan assets
Fair Value Measurements, Recurring [Member] | United States [Member] | Commingled Trust Funds [Member]
Fair value of plan assets	[1]	11,700		13,000
Fair Value Measurements, Recurring [Member] | United States [Member] | Commingled Trust Funds [Member] | Level 1 [Member]
Fair value of plan assets	[1]
Fair Value Measurements, Recurring [Member] | United States [Member] | Commingled Trust Funds [Member] | Level 2 [Member]
Fair value of plan assets	[1]
Fair Value Measurements, Recurring [Member] | United States [Member] | Commingled Trust Funds [Member] | Level 3 [Member]
Fair value of plan assets	[1]
Fair Value Measurements, Recurring [Member] | International [Member]
Fair value of plan assets		16,000		17,500
Fair Value Measurements, Recurring [Member] | International [Member] | Level 1 [Member]
Fair value of plan assets
Fair Value Measurements, Recurring [Member] | International [Member] | Level 2 [Member]
Fair value of plan assets		16,000		17,500
Fair Value Measurements, Recurring [Member] | International [Member] | Level 3 [Member]
Fair value of plan assets
Fair Value Measurements, Recurring [Member] | International [Member] | Insurance Contracts [Member]
Fair value of plan assets				17,500
Fair Value Measurements, Recurring [Member] | International [Member] | Insurance Contracts [Member] | Level 1 [Member]
Fair value of plan assets
Fair Value Measurements, Recurring [Member] | International [Member] | Insurance Contracts [Member] | Level 2 [Member]
Fair value of plan assets		16,000		17,500
Fair Value Measurements, Recurring [Member] | International [Member] | Insurance Contracts [Member] | Level 3 [Member]
Fair value of plan assets

[1] In accordance with ASC 820-10, certain investments that are measured at fair value using the net asset value (NAV) per share (or its equivalent) as a practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the fair value of plan assets.