Consolidated Statements Of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Retained Earnings	Trust for Savings Restoration Plan	Foreign Currency Translation	Gain (Loss) on Derivative Financial Instruments	Pension & Other Post-retirement Benefit Adjustment
Beginning Balance at Dec. 31, 2019	$ 376,749	$ 45,514	$ 530,478	$ (1,592)	$ (100,663)	$ (1,307)	$ (95,681)
Net Income (Loss) Attributable to Parent	(11,126)		(11,126)
Foreign currency translation adjustment (net of tax of $463)	(12,003)				(12,003)
Derivative financial instruments adjustment (net of tax of $547)	(2,517)					(2,517)
Amortization of prior service costs and net gains or losses (net of tax of $922)	5,862						5,862
Cash dividends declared ($0.12 per share)	(8,025)		(8,025)
Stock-based compensation expense	2,520	2,520
Repurchase of employee common stock for tax withholdings	(586)	(586)
Tredegar common stock purchased by trust for savings restoration plan			18	(18)
Ending Balance at Jun. 30, 2020	350,874	47,448	511,345	(1,610)	(112,666)	(3,824)	(89,819)
Foreign currency translation adjustment, tax (benefit)	1,106
Derivative financial instruments adjustment, tax (benefit)	$ 887
Cash dividends declared, per share	$ 0.24
Amortization of prior service costs and net gains or losses, tax	$ 1,671
Beginning Balance at Mar. 31, 2020	338,590	46,054	504,161	(1,601)	(112,192)	(5,082)	(92,750)
Net Income (Loss) Attributable to Parent	11,196
Foreign currency translation adjustment (net of tax of $463)	(474)				(474)
Derivative financial instruments adjustment (net of tax of $547)	1,258					1,258
Amortization of prior service costs and net gains or losses (net of tax of $922)	2,931						2,931
Cash dividends declared ($0.12 per share)	(4,021)		(4,021)
Stock-based compensation expense	1,394	1,394
Tredegar common stock purchased by trust for savings restoration plan			(9)	9
Ending Balance at Jun. 30, 2020	350,874	47,448	511,345	(1,610)	(112,666)	(3,824)	(89,819)
Foreign currency translation adjustment, tax (benefit)	177
Derivative financial instruments adjustment, tax (benefit)	$ 339
Cash dividends declared, per share	$ 0.12
Amortization of prior service costs and net gains or losses, tax	$ 835
Beginning Balance at Dec. 31, 2020	109,055	50,066	239,480	(2,087)	(84,149)	2,264	(96,519)
Net Income (Loss) Attributable to Parent	30,267
Foreign currency translation adjustment (net of tax of $463)	1,345				1,345
Derivative financial instruments adjustment (net of tax of $547)	1,232					1,232
Amortization of prior service costs and net gains or losses (net of tax of $922)	6,637						6,637
Cash dividends declared ($0.12 per share)	(8,070)		(8,070)
Stock-based compensation expense	1,959	1,959
Issued upon exercise of stock options	915
Tredegar common stock purchased by trust for savings restoration plan			(22)	22
Ending Balance at Jun. 30, 2021	143,340	52,940	261,699	(2,109)	(82,804)	3,496	(89,882)
Foreign currency translation adjustment, tax (benefit)	191
Derivative financial instruments adjustment, tax (benefit)	$ 359
Cash dividends declared, per share	$ 0.24
Amortization of prior service costs and net gains or losses, tax	$ 1,846
Beginning Balance at Mar. 31, 2021	115,987	51,557	244,496	(2,097)	(86,797)	2,028	(93,200)
Net Income (Loss) Attributable to Parent	21,236
Foreign currency translation adjustment (net of tax of $463)	3,993				3,993
Derivative financial instruments adjustment (net of tax of $547)	1,468					1,468
Amortization of prior service costs and net gains or losses (net of tax of $922)	3,318						3,318
Cash dividends declared ($0.12 per share)	(4,045)		(4,045)
Stock-based compensation expense	1,383	1,383
Tredegar common stock purchased by trust for savings restoration plan			(12)	12
Ending Balance at Jun. 30, 2021	143,340	$ 52,940	$ 261,699	$ (2,109)	$ (82,804)	$ 3,496	$ (89,882)
Foreign currency translation adjustment, tax (benefit)	463
Derivative financial instruments adjustment, tax (benefit)	$ 547
Cash dividends declared, per share	$ 0.12
Amortization of prior service costs and net gains or losses, tax	$ 922