CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Livermore Software Technology, LLC	Analytical Graphics Inc.	Common Stock	Common Stock Livermore Software Technology, LLC	Common Stock Analytical Graphics Inc.	Additional Paid-In Capital	Additional Paid-In Capital Livermore Software Technology, LLC	Additional Paid-In Capital Analytical Graphics Inc.	Retained Earnings	Treasury Stock	Treasury Stock Livermore Software Technology, LLC	Treasury Stock Analytical Graphics Inc.	Accumulated Other Comprehensive (Loss)/Income
Beginning balance at Dec. 31, 2019	$ 3,453,379			$ 946			$ 1,188,939			$ 3,370,706	$ (1,041,831)			$ (65,381)
Beginning balance, shares at Dec. 31, 2019				94,628							8,893
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Acquisition activity		$ 1,531	$ 218,348			$ 7		$ 1,030	$ 218,108			$ 501	$ 233
Acquisition activity, shares						638
Acquisition activity, treasury shares												(6)	(3)
Treasury shares acquired	$ (161,029)										$ (161,029)
Treasury shares acquired, shares	690										690
Stock-based compensation activity	$ 104,150						26,126				$ 78,024
Stock-based compensation activity, shares											(880)
Other comprehensive (loss)/income	47,606													47,606
Net income for the year	433,887									433,887
Ending balance at Dec. 31, 2020	4,097,872			$ 953			1,434,203			3,804,593	$ (1,124,102)			(17,775)
Ending balance, shares at Dec. 31, 2020				95,266							8,694
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Acquisition activity			3,888						3,069				$ 819
Acquisition activity, shares						1
Acquisition activity, treasury shares													(10)
Treasury shares acquired	$ (134,679)										$ (134,679)
Treasury shares acquired, shares	347										347
Stock-based compensation activity	$ 100,677						28,422				$ 72,255
Stock-based compensation activity, shares											(843)
Other comprehensive (loss)/income	(38,337)													(38,337)
Net income for the year	454,627									454,627
Ending balance at Dec. 31, 2021	4,484,048			$ 953			1,465,694			4,259,220	$ (1,185,707)			(56,112)
Ending balance, shares at Dec. 31, 2021				95,267							8,188
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Acquisition activity			$ 811						$ 511				$ 300
Acquisition activity, shares
Acquisition activity, treasury shares													(3)
Treasury shares acquired	$ (205,571)										$ (205,571)
Treasury shares acquired, shares	725										725
Stock-based compensation activity	$ 129,463						74,112				$ 55,351
Stock-based compensation activity, shares											(593)
Other comprehensive (loss)/income	(66,610)													(66,610)
Net income for the year	523,710									523,710
Ending balance at Dec. 31, 2022	$ 4,865,851			$ 953			$ 1,540,317			$ 4,782,930	$ (1,335,627)			$ (122,722)
Ending balance, shares at Dec. 31, 2022				95,267							8,317