Segment Reporting - Summarized Financial Information for Company's Reportable Segments (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Rental revenues		$ 66,532	$ 65,502
Rental related services revenues		17,591	15,367
Sales and other revenues		9,576	9,319
Total revenues		93,699	90,188
Depreciation of rental equipment		18,540	18,682
Gross profit		40,655	39,087
Selling and administrative expenses		26,397	25,212
Income (loss) from operations		14,258	13,875
Interest (expense) income allocation		(3,556)	(2,391)
Income (loss) before provision for income taxes		10,853	11,316
Rental equipment acquisitions (dispositions)		19,290	35,254
Accounts receivable, net (period end)		91,883	89,361	$ 95,263
Rental equipment, at cost (period end)		1,317,622	1,254,316	1,310,083
Rental equipment, net book value (period end)		867,215	839,078	$ 869,601
Mobile Modular [Member]
Segment Reporting Information [Line Items]
Rental revenues		31,155	26,408
Rental related services revenues		11,205	9,103
Sales and other revenues		2,724	3,373
Total revenues		45,084	38,884
Depreciation of rental equipment		5,126	4,561
Gross profit		20,653	15,704
Selling and administrative expenses		12,462	11,356
Income (loss) from operations		8,191	4,348
Interest (expense) income allocation		(1,947)	(1,253)
Income (loss) before provision for income taxes		6,244	3,095
Rental equipment acquisitions (dispositions)		11,579	16,359
Accounts receivable, net (period end)		50,915	45,818
Rental equipment, at cost (period end)		747,475	678,990
Rental equipment, net book value (period end)		$ 535,308	$ 484,598
Utilization (period end)	[1]	75.40%	74.50%
Average utilization	[1]	76.10%	74.20%
TRS-RenTelco [Member]
Segment Reporting Information [Line Items]
Rental revenues		$ 20,928	$ 22,111
Rental related services revenues		784	656
Sales and other revenues		6,272	5,327
Total revenues		27,984	28,094
Depreciation of rental equipment		9,388	10,152
Gross profit		11,016	11,310
Selling and administrative expenses		5,797	6,118
Income (loss) from operations		5,219	5,192
Interest (expense) income allocation		(730)	(529)
Income (loss) before provision for income taxes		4,640	4,495
Rental equipment acquisitions (dispositions)		7,729	16,230
Accounts receivable, net (period end)		21,393	23,095
Rental equipment, at cost (period end)		260,324	269,575
Rental equipment, net book value (period end)		$ 98,291	$ 109,887
Utilization (period end)	[1]	59.90%	58.60%
Average utilization	[1]	59.60%	59.90%
Adler Tanks [Member]
Segment Reporting Information [Line Items]
Rental revenues		$ 14,449	$ 16,983
Rental related services revenues		5,602	5,608
Sales and other revenues		432	307
Total revenues		20,483	22,898
Depreciation of rental equipment		4,026	3,969
Gross profit		8,942	12,007
Selling and administrative expenses		7,262	6,918
Income (loss) from operations		1,680	5,089
Interest (expense) income allocation		(934)	(657)
Income (loss) before provision for income taxes		746	4,432
Rental equipment acquisitions (dispositions)		(18)	2,665
Accounts receivable, net (period end)		15,386	18,316
Rental equipment, at cost (period end)		309,823	305,751
Rental equipment, net book value (period end)		$ 233,616	$ 244,593
Utilization (period end)	[1]	51.00%	61.10%
Average utilization	[1]	50.30%	61.10%
Enviroplex [Member]
Segment Reporting Information [Line Items]
Sales and other revenues	[2]	$ 148	$ 312
Total revenues	[2]	148	312
Gross profit	[2]	44	66
Selling and administrative expenses	[2]	876	820
Income (loss) from operations	[2]	(832)	(754)
Interest (expense) income allocation	[2]	55	48
Income (loss) before provision for income taxes	[2]	(777)	(706)
Accounts receivable, net (period end)	[2]	$ 4,189	$ 2,132

[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 $148 and $316 for the three months ended March 31, 2016 and 2015, respectively, which include inter-segment sales to Mobile Modular of $0 and $4, respectively, which have been eliminated in consolidation.