Effects of Share-Based Compensation Awards on Diluted Weighted-Average Number of Shares Outstanding used in Calculating Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Earnings Per Share [Abstract]
Net income attributable to Kraton	$ 3,829	$ 12,407	$ 81	$ 28,760
Amounts allocated to unvested restricted shares	(54)	(120)	(1)	(243)
Net Income, Basic, Amounts available to common stockholders	3,775	12,287	80	28,517
Amounts allocated to unvested restricted shares	54	120	1	243
Net Income, Diluted, Less: amounts reallocated to unvested restricted shares	$ (53,000)	$ (119,000)	$ (1,000)	$ (241,000)
Net Income, Diluted, Amounts available to stockholders and assumed conversions	$ 3,776	$ 12,288	$ 80	$ 28,519
Weighted Average Shares Outstanding, Basic, As reported	32,528	32,241	32,443	32,191
Weighted Average Shares Outstanding, amounts allocated to unvested restricted shares	(455)	(311)	(375)	(272)
Weighted Average Shares Outstanding, Basic, Amounts available to common stockholders	32,073	31,930	32,068	31,919
Weighted Average Shares Outstanding, amounts allocated to unvested restricted shares	455	311	375	272
Weighted Average Shares Outstanding, Diluted, Non participating Share Units	125	29	92	29
Weighted Average Shares Outstanding, Diluted, Stock options added under the treasury stock method	180	213	231	261
Weighted Average Shares Outstanding, Diluted, amounts reallocated to unvested restricted shares	(455)	(311)	(375)	(272)
Amounts available to stockholders and assumed conversions	32,378	32,172	32,391	32,209
Earnings per share, basic	$ 0.12	$ 0.38	$ 0.00	$ 0.89
Earnings per share, diluted	$ 0.12	$ 0.38	$ 0.00	$ 0.89