UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Income Statement [Abstract]
Revenue	$ 108,892	$ 90,951	$ 213,910	$ 176,763
Cost of revenue	21,110	14,957	40,981	29,602
Gross profit	87,782	75,994	172,929	147,161
Operating expenses
Sales and marketing	45,011	35,000	86,318	68,921
Research and development	23,801	19,288	45,713	36,592
General and administrative	23,315	18,312	45,317	36,786
Total operating expenses	92,127	72,600	177,348	142,299
(Loss) income from operations	(4,345)	3,394	(4,419)	4,862
Other income, net	2,287	2,616	6,459	6,255
(Loss) income before income taxes	(2,058)	6,010	2,040	11,117
Provision for income taxes	4,719	4,649	8,162	7,753
Net (loss) income	(6,777)	1,361	(6,122)	3,364
Net loss attributable to noncontrolling interest in consolidated subsidiaries	(210)	(298)	(404)	(433)
Net (loss) income attributable to Semrush Holdings, Inc.	$ (6,567)	$ 1,659	$ (5,718)	$ 3,797
Net (loss) income attributable to Semrush Holdings, Inc. per share attributable to common stockholder—basic (in dollars per share)	$ (0.04)	$ 0.01	$ (0.04)	$ 0.03
Net (loss) income attributable to Semrush Holdings, Inc. per share attributable to common stockholders—diluted (in dollars per share)	$ (0.04)	$ 0.01	$ (0.04)	$ 0.03
Weighted-average number of shares of common stock used in computing net (loss) income per share attributable to common stockholders—basic (in shares)	148,310,571	145,678,323	147,765,447	145,121,951
Weighted-average number of shares of common stock used in computing net (loss) income per share attributable to common stockholders—diluted (in shares)	148,310,571	148,825,311	147,765,447	148,261,407
Comprehensive income (loss)
Net (loss) income	$ (6,777)	$ 1,361	$ (6,122)	$ 3,364
Other comprehensive (loss) income:
Foreign currency translation adjustments	3,050	(119)	4,370	(604)
Unrealized gain (loss) on investments	123	(184)	713	(928)
Comprehensive (loss) income	(3,604)	1,058	(1,039)	1,832
Comprehensive loss attributable to noncontrolling interest in consolidated subsidiaries	(210)	(298)	(404)	(433)
Comprehensive (loss) income attributable to Semrush Holdings, Inc.	$ (3,394)	$ 1,356	$ (635)	$ 2,265