CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 115,714	$ 103,848	$ 330,565	$ 276,710
Other comprehensive income (loss):
Reclassification adjustments for derivatives, net of tax	0	672	2,531	3,982
Pension and other postretirement adjustments, net of tax	840	291	10,795	1,956
Cumulative translation adjustment	(28,703)	47,343	(56,887)	40,158
Other comprehensive income (loss)	(27,863)	48,306	(43,561)	46,096
Comprehensive income	87,851	152,154	287,004	322,806
Comprehensive loss attributable to noncontrolling interest	30	0	85	0
Comprehensive income attributable to IDEX	$ 87,881	$ 152,154	$ 287,089	$ 322,806