Segment Reporting - Summarized Financial Information for Company's Reportable Segments (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Rental revenues		$ 474,336	$ 389,663	$ 333,988
Rental related services revenues		138,160	94,963	75,210
Sales and other revenues		219,346	151,039	125,393
Total revenues		831,842	635,665	534,591
Depreciation of rental equipment		88,912	80,425	75,445
Gross profit		393,633	290,208	247,322
Selling and administrative expenses		(207,539)	(142,914)	(123,058)
Other income		3,618
Income (loss) from operations		189,712	147,294	124,264
Interest expense (income) allocation		40,560	12,230	8,244
Income before provision/benefit for income taxes		149,462	134,686	115,810
Rental equipment acquisitions		233,112	191,535	249,489
Accounts receivable, net (period end)		227,368	169,851	143,121
Rental equipment, at cost (period end)		1,904,803	1,521,535	1,401,485
Rental equipment, net book value (period end)		1,329,323	990,316	913,437
Mobile Modular [Member]
Segment Reporting Information [Line Items]
Rental revenues		285,553	206,070	175,626
Rental related services revenues		114,511	74,756	59,756
Sales and other revenues		162,172	98,385	65,983
Total revenues		562,236	379,211	301,365
Depreciation of rental equipment		36,921	28,373	25,852
Gross profit		257,921	161,885	136,618
Selling and administrative expenses		(138,574)	(85,769)	(72,091)
Other income		2,329
Income (loss) from operations		121,676	76,116	64,526
Interest expense (income) allocation		29,724	8,657	5,553
Income before provision/benefit for income taxes		91,952	67,459	58,973
Rental equipment acquisitions		176,200	87,535	151,625
Accounts receivable, net (period end)		175,360	124,184	101,839
Rental equipment, at cost (period end)		1,291,093	929,636	879,272
Rental equipment, net book value (period end)		$ 967,712	$ 637,151	$ 603,497
Utilization (period end)	[1]	79.40%	80.30%	75.30%
Average utilization	[1]	79.70%	78.00%	75.40%
Portable Storage [Member]
Segment Reporting Information [Line Items]
Rental revenues		$ 74,536	$ 62,218	$ 44,943
Rental related services revenues		20,510	17,095	12,574
Sales and other revenues		6,091	3,193	4,434
Total revenues		101,137	82,506	61,951
Depreciation of rental equipment		3,514	2,799	2,219
Gross profit		68,880	55,302	39,422
Selling and administrative expenses		(31,537)	(24,465)	(20,512)
Other income		457
Income (loss) from operations		37,800	30,837	18,910
Interest expense (income) allocation		4,950	1,518	880
Income before provision/benefit for income taxes		32,850	29,319	18,030
Rental equipment acquisitions		27,967	34,072	36,767
Accounts receivable, net (period end)		16,057	14,923	10,456
Rental equipment, at cost (period end)		236,123	193,632	160,822
Rental equipment, net book value (period end)		$ 217,315	$ 178,241	$ 148,040
Utilization (period end)	[1]	71.50%	82.60%	82.50%
Average utilization	[1]	77.30%	84.80%	81.00%
TRS-RenTelco [Member]
Segment Reporting Information [Line Items]
Rental revenues		$ 114,247	$ 121,375	$ 113,419
Rental related services revenues		3,139	3,112	2,880
Sales and other revenues		30,891	26,291	23,895
Total revenues		148,277	150,778	140,194
Depreciation of rental equipment		48,477	49,253	47,374
Gross profit		62,604	67,899	61,394
Selling and administrative expenses		(30,962)	(27,245)	(25,152)
Other income		832
Income (loss) from operations		32,474	40,654	36,243
Interest expense (income) allocation		8,146	3,294	2,270
Income before provision/benefit for income taxes		24,638	36,982	33,763
Rental equipment acquisitions		28,945	69,928	61,097
Accounts receivable, net (period end)		25,511	26,442	22,115
Rental equipment, at cost (period end)		377,587	398,267	361,391
Rental equipment, net book value (period end)		$ 144,296	$ 174,924	$ 161,900
Utilization (period end)	[1]	55.90%	59.40%	62.90%
Average utilization	[1]	58.90%	64.20%	67.00%
Enviroplex [Member]
Segment Reporting Information [Line Items]
Sales and other revenues	[2]	$ 20,192	$ 23,170	$ 31,081
Total revenues	[2]	20,192	23,170	31,081
Gross profit	[2]	4,228	5,122	9,888
Selling and administrative expenses	[2]	(6,466)	(5,435)	(5,303)
Income (loss) from operations	[2]	(2,238)	(313)	4,585
Interest expense (income) allocation	[2]	(2,260)	(1,239)	(459)
Income before provision/benefit for income taxes	[2]	22	926	5,044
Accounts receivable, net (period end)	[2]	$ 10,440	$ 4,302	$ 8,711

[1] Utilization is calculated each month by dividing the cost of rental equipment on rent by the total cost of rental equipment excluding new equipment inventory and accessory equipment. The average utilization for the period is calculated using the average costs of rental equipment.

[2] Gross Enviroplex sales revenues were $22,615, $24,162 and $32,095 in 2022, 2021 and 2020, respectively. There were $2,422, $992 and $969 inter-segment sales to Mobile Modular in 2023, 2022 and 2021, respectively, which have been eliminated in consolidation.