Quarterly Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 31, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule Of Quarterly Financial Information [Line Items]
Net sales	$ 271,633	$ 273,054	$ 251,578	$ 165,804	$ 186,260	$ 164,585	$ 177,544	$ 165,070	$ 962,069	$ 693,459	$ 715,903
Gross profit	117,920	98,743	88,668	71,352	79,384	70,132	77,570	67,128	376,683	294,214	307,383
Net income	$ 9,312	$ (1,068)	$ (14,669)	$ 14,312	$ 20,541	$ 17,807	$ 19,781	$ 16,397	$ 7,887	$ 74,526	$ 68,825
Basic income per share attributable to Entegris, Inc.	$ 0.07	$ (0.01)	$ (0.11)	$ 0.10	$ 0.15	$ 0.13	$ 0.14	$ 0.12	$ 0.06	$ 0.54	$ 0.50
Diluted income per share attributable to Entegris, Inc.	$ 0.07	$ (0.01)	$ (0.11)	$ 0.10	$ 0.15	$ 0.13	$ 0.14	$ 0.12	$ 0.06	$ 0.53	$ 0.50