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Stockholders' Equity - Narratives (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended												12 Months Ended
	Dec. 05, 2019	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Nov. 04, 2021	May 31, 2021	Jul. 31, 2019	Dec. 31, 2018	Apr. 26, 2018
Class of Stock [Line Items]
Shares, Issued																					38,097,525
Sale of Stock, Price Per Share	$ 13.125																				$ 15.00
Sale of Stock, Transaction Date	11,175,927
Decrease in percentage of shares outstanding (percent)	7.00%
Stock Repurchase Program, Authorized Amount																	$ 150,000		$ 100,000
Purchase of treasury shares														$ 50,000	$ 30,099	$ 10,868
Stock Repurchase Program, Remaining Authorized Repurchase Amount		$ 159,000												$ 159,000
Dividends paid (in dollars per share)		$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.085	$ 0.085	$ 0.085	$ 0.085	$ 0.085	$ 0.04	$ 0.115	$ 0.34
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Repurchase of Shares by Subsidiary	$ 250,000
Common Stock
Class of Stock [Line Items]
Shares, Issued		263,255,708				267,188,547				270,485,308				263,255,708	267,188,547	270,485,308				290,537,612
Stock Repurchased and Retired During Period, Shares														4,658,544	3,328,574	1,004,685
Affiliated Entity | Common Stock
Class of Stock [Line Items]
Stock Repurchased and Retired During Period, Shares	19,047,619
Brookfield [Member] | GrafTech International Ltd [Member]
Class of Stock [Line Items]
Equity Method Investment, Ownership Percentage		24.30%				55.30%								24.30%	55.30%			24.00%

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