Segment Reporting - Summarized Financial Information for Company's Reportable Segments (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Rental revenues		$ 67,305	$ 65,809	$ 132,807	$ 128,239
Rental related services revenues		17,227	15,146	32,594	28,658
Sales and other revenues				20,813	26,408
Total revenues		96,026	95,745	186,214	183,305
Depreciation of rental equipment		19,016	17,924	37,698	35,821
Gross profit		40,918	42,079	80,005	80,717
Selling and administrative expenses		24,453	23,840	49,665	47,251
Income (loss) from operations		16,465	18,239	30,340	33,466
Interest (expense) income allocation				(4,738)	(4,538)
Gain on sale of property, plant and equipment			812		812
Income (loss) before provision for income taxes		14,033	16,794	25,349	29,730
Rental equipment acquisitions				74,687	71,656
Accounts receivable, net (period end)		93,974	89,084	93,974	89,084	$ 101,294
Rental equipment, at cost (period end)		1,277,244	1,184,612	1,277,244	1,184,612	1,229,638
Rental equipment, net book value (period end)		856,489	795,532	856,489	795,532	$ 825,750
Mobile Modular [Member]
Segment Reporting Information [Line Items]
Rental revenues				54,088	44,212
Rental related services revenues				19,591	15,328
Sales and other revenues				7,325	11,415
Total revenues				81,004	70,955
Depreciation of rental equipment				9,280	7,842
Gross profit				32,266	25,774
Selling and administrative expenses				22,642	19,830
Income (loss) from operations				9,624	5,944
Interest (expense) income allocation				(2,481)	(2,290)
Gain on sale of property, plant and equipment					341
Income (loss) before provision for income taxes				7,143	3,995
Rental equipment acquisitions				38,691	38,177
Accounts receivable, net (period end)		46,913	42,947	46,913	42,947
Rental equipment, at cost (period end)		699,781	626,457	699,781	626,457
Rental equipment, net book value (period end)		501,071	443,086	$ 501,071	$ 443,086
Utilization (period end)	[1]			74.30%	71.60%
Average utilization	[1]			74.30%	70.20%
TRS-RenTelco [Member]
Segment Reporting Information [Line Items]
Rental revenues				$ 44,000	$ 48,184
Rental related services revenues				1,450	1,617
Sales and other revenues				10,545	11,977
Total revenues				55,995	61,778
Depreciation of rental equipment				20,477	20,539
Gross profit				22,751	28,138
Selling and administrative expenses				11,611	12,004
Income (loss) from operations				11,140	16,134
Interest (expense) income allocation				(1,053)	(1,053)
Gain on sale of property, plant and equipment					276
Income (loss) before provision for income taxes				9,834	15,347
Rental equipment acquisitions				30,077	18,387
Accounts receivable, net (period end)		23,547	22,500	23,547	22,500
Rental equipment, at cost (period end)		269,668	259,907	269,668	259,907
Rental equipment, net book value (period end)		112,275	103,816	$ 112,275	$ 103,816
Utilization (period end)	[1]			60.30%	62.20%
Average utilization	[1]			59.80%	58.30%
Adler Tanks [Member]
Segment Reporting Information [Line Items]
Rental revenues				$ 34,719	$ 35,843
Rental related services revenues				11,553	11,713
Sales and other revenues				742	769
Total revenues				47,014	48,325
Depreciation of rental equipment				7,941	7,440
Gross profit				24,380	26,060
Selling and administrative expenses				13,819	13,836
Income (loss) from operations				10,561	12,224
Interest (expense) income allocation				(1,297)	(1,284)
Gain on sale of property, plant and equipment					195
Income (loss) before provision for income taxes				9,264	11,135
Rental equipment acquisitions				5,919	15,092
Accounts receivable, net (period end)		20,310	21,057	20,310	21,057
Rental equipment, at cost (period end)		307,795	298,248	307,795	298,248
Rental equipment, net book value (period end)		243,143	248,630	$ 243,143	$ 248,630
Utilization (period end)	[1]			61.70%	61.50%
Average utilization	[1]			60.90%	61.80%
Enviroplex [Member]
Segment Reporting Information [Line Items]
Sales and other revenues	[2]			$ 2,201	$ 2,247
Total revenues	[2]			2,201	2,247
Gross profit	[2]			608	745
Selling and administrative expenses	[2]			1,593	1,581
Income (loss) from operations	[2]			(985)	(836)
Interest (expense) income allocation	[2]			93	89
Income (loss) before provision for income taxes	[2]			(892)	(747)
Accounts receivable, net (period end)	[2]	$ 3,204	$ 2,580	$ 3,204	$ 2,580

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

[2] Gross Enviroplex sales revenues were $2,208 and $3,323 for the six months ended June 30, 2015 and 2014, respectively, which includes inter-segment sales to Mobile Modular of $7 and $1,076, respectively, which have been eliminated in consolidation.