CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Revenue	$ 376,815	$ 307,675	$ 254,316
Cost of revenue	65,477	52,327	48,553
Gross profit	311,338	255,348	205,763
Operating expenses
Sales and marketing	144,340	126,871	126,889
Research and development	80,080	57,442	41,204
General and administrative	78,610	77,410	62,779
Exit Costs	0	1,292	11,264
Total operating expenses	303,030	263,015	242,136
Income (loss) from operations	8,308	(7,667)	(36,373)
Other income, net	12,094	12,313	3,456
Income (loss) before income taxes	20,402	4,646	(32,917)
Provision for income taxes	13,027	3,696	931
Net income (loss)	7,375	950	(33,848)
Net loss attributable to noncontrolling interest in consolidated subsidiaries	(861)	0	0
Net income (loss) attributable to Semrush Holdings, Inc.	$ 8,236	$ 950	$ (33,848)
Net income (loss) per share attributable to common stockholders
Net income (loss) attributable to Semrush Holdings, Inc. per share attributable to common stockholders—basic (in dollars per share)	$ 0.06	$ 0.01	$ (0.24)
Net income (loss) attributable to Semrush Holdings, Inc. per share attributable to common stockholders—diluted (in dollars per share)	$ 0.06	$ 0.01	$ (0.24)
Weighted-average number of shares of common stock used in computing net income (loss) per share attributable to common stockholders
Weighted-average number of shares of common stock used in computing net income (loss) per share attributable to common stockholders—basic (in shares)	145,864,755	142,593,000	141,160,000
Weighted-average number of shares of common stock used in computing net income (loss) per share attributable to common stockholders—diluted (in shares)	148,861,846	146,065,333	141,160,000
Comprehensive income (loss)
Net income (loss)	$ 7,375	$ 950	$ (33,848)
Other comprehensive income (loss):
Foreign currency translation adjustments	(1,585)	451	(851)
Unrealized gain (loss) on investments	116	3	(125)
Comprehensive income (loss)	5,906	1,404	(34,824)
Comprehensive loss attributable to noncontrolling interest in consolidated subsidiaries	(861)	0	0
Comprehensive income (loss) attributable to Semrush Holdings, Inc.	$ 6,767	$ 1,404	$ (34,824)