Earnings per Share ("EPS") - Effects of Share-Based Compensation Awards on Diluted Weighted-Average Number of Shares Outstanding used in Calculating Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Basic:
Net income (loss) attributable to Kraton	$ 170,226	$ (225,602)	$ 51,305
Amounts allocated to unvested restricted shares	56	(701)	399
Amounts available to common stockholders	$ 170,170	$ (224,901)	$ 50,906
Weighted Average Shares Outstanding, Basic
As reported (in shares)	32,108	31,845	31,828
Amounts allocated to unvested restricted shares (in shares)	(10)	(99)	(247)
Amounts available to common stockholders (in shares)	32,098	31,746	31,581
Diluted:
Amounts allocated to unvested restricted shares	$ 56	$ (701)	$ 399
Amounts reallocated to unvested restricted shares	(55)	701	(395)
Amounts available to stockholders and assumed conversions	$ 170,171	$ (224,901)	$ 50,910
Weighted Average Shares Outstanding, Diluted
Amounts allocated to unvested restricted shares (in shares)	10	99	247
Non participating share units (in shares)	474	0	259
Stock options added under the treasury stock method (in shares)	70	0	41
Amounts reallocated to unvested restricted shares (in shares)	(10)	(99)	(247)
Amounts available to stockholders and assumed conversions (in shares)	32,642	31,746	31,881
Earnings Per Share, Basic (in dollars per share)	$ 5.30	$ (7.08)	$ 1.61
Earnings Per Share, Diluted (in dollars per share)	$ 5.21	$ (7.08)	$ 1.60