Earnings (Loss) Per Share - Schedule of Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022
Numerator
Net loss attributable to Coherent Corp.	$ (26,991)	$ (45,072)	$ (94,525)	$ (83,770)
Deduct Series A preferred stock dividends	(30,580)	(35,889)	(60,753)	(71,466)
Basic loss available to common shareholders	(57,571)	(80,961)	(155,278)	(155,236)
Diluted loss available to common shareholders	$ (57,571)	$ (80,961)	$ (155,278)	$ (155,236)
Denominator
Diluted weighted average common shares (in shares)	151,564	138,623	150,946	135,951
Basic loss per common share (in usd per share)	$ (0.38)	$ (0.58)	$ (1.03)	$ (1.14)
Diluted loss per common share (in usd per share)	$ (0.38)	$ (0.58)	$ (1.03)	$ (1.14)
Deduct Series A preferred stock dividends
Numerator
Deduct Series A preferred stock dividends	$ 0	$ (6,900)	$ 0	$ (13,800)
Deduct Series B dividends and deemed dividends
Numerator
Deduct Series A preferred stock dividends	(29,235)	(27,821)	(58,109)	(55,298)
Deduct Series B dividends and deemed dividends	$ (30,580)	$ (28,989)	$ (60,753)	$ (57,666)