Segment Reporting - Summarized Financial Information for Company's Reportable Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]
Rental Revenues	$ 65,809	$ 63,043	$ 128,239	$ 123,644
Rental Related Services Revenues	15,146	12,661	28,658	23,506
Sales and Other Revenues			26,408	28,748
Total Revenues	95,745	87,156	183,305	175,898
Depreciation of Rental Equipment	17,924	16,626	35,821	33,228
Gross Profit	42,079	40,169	80,717	79,196
Selling and Administrative Expenses	23,840	21,792	47,251	43,430
Income (Loss) from Operations	18,239	18,377	33,466	35,766
Interest Expense (Income) Allocation			4,538	4,360
Gain on Sale of Property, Plant and Equipment	812		812
Income (Loss) before Provision for Income Taxes	16,794	16,197	29,730	31,354
Rental Equipment Acquisitions			71,656	60,029
Accounts Receivable, net (period end)	89,084	87,286	89,084	87,286	87,650
Rental Equipment, at cost (period end)	1,184,612	1,104,218	1,184,612	1,104,218	1,144,168
Rental Equipment, net book value (period end)	795,532	737,636	795,532	737,636	767,010
Mobile Modular [Member]
Segment Reporting Information [Line Items]
Rental Revenues			44,212	39,288
Rental Related Services Revenues			15,328	12,491
Sales and Other Revenues			11,415	6,715
Total Revenues			70,955	58,494
Depreciation of Rental Equipment			7,842	7,089
Gross Profit			25,774	22,894
Selling and Administrative Expenses			19,830	17,371
Income (Loss) from Operations			5,944	5,523
Interest Expense (Income) Allocation			2,290	2,158
Gain on Sale of Property, Plant and Equipment			341
Income (Loss) before Provision for Income Taxes			3,995	3,365
Rental Equipment Acquisitions			38,177	21,521
Accounts Receivable, net (period end)	42,947	37,573	42,947	37,573
Rental Equipment, at cost (period end)	626,457	570,352	626,457	570,352
Rental Equipment, net book value (period end)	443,086	397,702	443,086	397,702
Utilization (period end)			71.60%	67.60%
Average Utilization			70.20%	66.70%
TRS-RenTelco [Member]
Segment Reporting Information [Line Items]
Rental Revenues			48,184	50,179
Rental Related Services Revenues			1,617	1,412
Sales and Other Revenues			11,977	14,252
Total Revenues			61,778	65,843
Depreciation of Rental Equipment			20,539	19,474
Gross Profit			28,138	31,010
Selling and Administrative Expenses			12,004	12,400
Income (Loss) from Operations			16,134	18,610
Interest Expense (Income) Allocation			1,053	1,089
Gain on Sale of Property, Plant and Equipment			276
Income (Loss) before Provision for Income Taxes			15,347	17,469
Rental Equipment Acquisitions			18,387	22,655
Accounts Receivable, net (period end)	22,500	22,750	22,500	22,750
Rental Equipment, at cost (period end)	259,907	264,429	259,907	264,429
Rental Equipment, net book value (period end)	103,816	105,869	103,816	105,869
Utilization (period end)			62.20%	63.30%
Average Utilization			58.30%	63.70%
Adler Tanks [Member]
Segment Reporting Information [Line Items]
Rental Revenues			35,843	34,177
Rental Related Services Revenues			11,713	9,603
Sales and Other Revenues			769	1,354
Total Revenues			48,325	45,134
Depreciation of Rental Equipment			7,440	6,665
Gross Profit			26,060	24,557
Selling and Administrative Expenses			13,836	12,097
Income (Loss) from Operations			12,224	12,460
Interest Expense (Income) Allocation			1,284	1,213
Gain on Sale of Property, Plant and Equipment			195
Income (Loss) before Provision for Income Taxes			11,135	11,247
Rental Equipment Acquisitions			15,092	15,853
Accounts Receivable, net (period end)	21,057	24,139	21,057	24,139
Rental Equipment, at cost (period end)	298,248	269,437	298,248	269,437
Rental Equipment, net book value (period end)	248,630	234,065	248,630	234,065
Utilization (period end)			61.50%	68.70%
Average Utilization			61.80%	65.50%
Enviroplex [Member]
Segment Reporting Information [Line Items]
Rental Revenues
Rental Related Services Revenues
Sales and Other Revenues			2,247	6,427
Total Revenues			2,247	6,427
Depreciation of Rental Equipment
Gross Profit			745	735
Selling and Administrative Expenses			1,581	1,562
Income (Loss) from Operations			(836)	(827)
Interest Expense (Income) Allocation			(89)	(100)
Income (Loss) before Provision for Income Taxes			(747)	(727)
Rental Equipment Acquisitions
Accounts Receivable, net (period end)	2,580	2,824	2,580	2,824
Rental Equipment, at cost (period end)
Rental Equipment, net book value (period end)