CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 102,179	$ 70,864	$ 214,851	$ 172,862
Other comprehensive income (loss):
Reclassification adjustments for derivatives, net of tax	1,867	2,116	2,531	3,310
Pension and other postretirement adjustments, net of tax	9,210	(631)	9,955	1,665
Cumulative translation adjustment	20,255	19,271	(28,184)	(7,185)
Other comprehensive income (loss)	31,332	20,756	(15,698)	(2,210)
Comprehensive income	133,511	91,620	199,153	170,652
Comprehensive (income) loss attributable to noncontrolling interest	21	0	55	0
Comprehensive income attributable to IDEX	$ 133,532	$ 91,620	$ 199,208	$ 170,652