Segment Reporting - Summarized Financial Information for Company's Reportable Segments (Detail) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Rental revenues		$ 70,352	$ 67,757	$ 66,747	$ 66,532	$ 70,694	$ 70,195	$ 67,305	$ 65,502	$ 271,388	$ 273,696	$ 269,575
Rental related services revenues										75,859	73,314	64,132
Sales and other revenues										76,833	57,534	74,415
Total revenues		105,283	121,993	103,105	93,699	105,282	113,048	96,026	90,188	424,080	404,544	408,122
Depreciation of rental equipment										72,197	75,213	72,678
Gross profit		49,323	50,433	43,756	40,655	46,756	50,146	40,918	39,087	184,167	176,907	182,219
Selling and administrative expenses										104,908	99,950	96,859
Income (loss) from operations		22,696	24,232	18,073	14,258	21,467	25,150	16,465	13,875	79,259	76,957	85,360
Interest expense (income) allocation										(12,207)	(10,092)	9,280
Income before provision for income taxes		19,795	21,277	15,006	10,853	18,523	22,505	14,033	11,316	66,931	66,377	76,561
Rental equipment acquisitions										74,634	133,378	148,602
Accounts receivable, net (period end)		96,877				95,017				96,877	95,017	101,156
Rental equipment, at cost (period end)		1,324,057				1,310,083				1,324,057	1,310,083	1,229,638
Rental equipment, net book value (period end)		856,371	$ 862,528	$ 868,422	$ 867,215	869,601	$ 864,277	$ 856,489	$ 839,078	856,371	869,601	825,750
Mobile Modular [Member]
Segment Reporting Information [Line Items]
Rental revenues										130,496	115,986	96,457
Rental related services revenues										49,206	45,616	35,263
Sales and other revenues										29,810	22,682	29,855
Total revenues										209,512	184,284	161,575
Depreciation of rental equipment										21,001	19,246	16,536
Gross profit										93,816	78,771	63,455
Selling and administrative expenses										51,432	46,496	42,069
Income (loss) from operations										42,384	32,275	21,386
Interest expense (income) allocation										(6,804)	(5,363)	4,768
Income before provision for income taxes										35,580	26,912	16,959
Rental equipment acquisitions										43,099	79,622	82,792
Accounts receivable, net (period end)		55,916				53,550				55,916	53,550	46,659
Rental equipment, at cost (period end)		769,190				736,875				769,190	736,875	664,340
Rental equipment, net book value (period end)		544,421				529,483				$ 544,421	$ 529,483	$ 473,960
Utilization (period end)	[1]									77.30%	76.90%	75.00%
Average utilization	[1]									76.60%	75.80%	72.30%
TRS-RenTelco [Member]
Segment Reporting Information [Line Items]
Rental revenues										$ 82,307	$ 89,208	$ 99,020
Rental related services revenues										2,846	3,055	3,331
Sales and other revenues										23,464	22,754	25,951
Total revenues										108,617	115,017	128,302
Depreciation of rental equipment										35,256	39,974	40,935
Gross profit										45,797	47,836	60,249
Selling and administrative expenses										21,896	22,930	23,736
Income (loss) from operations										23,901	24,906	36,513
Interest expense (income) allocation										(2,465)	(2,194)	2,075
Income before provision for income taxes										21,315	22,224	34,383
Rental equipment acquisitions										30,505	44,316	45,158
Accounts receivable, net (period end)		19,506				21,784				19,506	21,784	28,849
Rental equipment, at cost (period end)		246,325				262,945				246,325	262,945	261,995
Rental equipment, net book value (period end)		90,172				102,191				$ 90,172	$ 102,191	$ 105,729
Utilization (period end)	[1]									61.00%	58.70%	59.80%
Average utilization	[1]									60.60%	60.50%	60.40%
Adler Tanks [Member]
Segment Reporting Information [Line Items]
Rental revenues										$ 58,585	$ 68,502	$ 74,098
Rental related services revenues										23,807	24,643	25,538
Sales and other revenues										1,438	1,486	1,152
Total revenues										83,830	94,631	100,788
Depreciation of rental equipment										15,940	15,993	15,207
Gross profit										37,409	47,397	53,452
Selling and administrative expenses										27,610	27,494	27,424
Income (loss) from operations										9,799	19,903	26,028
Interest expense (income) allocation										(3,200)	(2,729)	2,618
Income before provision for income taxes										6,599	17,174	23,605
Rental equipment acquisitions										1,030	9,440	20,652
Accounts receivable, net (period end)		16,150				17,955				16,150	17,955	21,031
Rental equipment, at cost (period end)		308,542				310,263				308,542	310,263	303,303
Rental equipment, net book value (period end)		221,778				237,927				$ 221,778	$ 237,927	$ 246,061
Utilization (period end)	[1]									50.70%	49.70%	63.90%
Average utilization	[1]									50.10%	58.30%	62.90%
Enviroplex [Member]
Segment Reporting Information [Line Items]
Sales and other revenues	[2]									$ 22,121	$ 10,612	$ 17,457
Total revenues	[2]									22,121	10,612	17,457
Gross profit	[2]									7,145	2,903	5,063
Selling and administrative expenses	[2]									3,970	3,030	3,630
Income (loss) from operations	[2]									3,175	(127)	1,433
Interest expense (income) allocation	[2]									262	194	(181)
Income before provision for income taxes	[2]									3,437	67	1,614
Accounts receivable, net (period end)	[2]	$ 5,305				$ 1,728				$ 5,305	$ 1,728	$ 4,617

[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 $22,206, $11,530 and $19,017 in 2016, 2015 and 2014, respectively, which includes inter-segment sales to Mobile Modular of $85, $918 and $1,560, which have been eliminated in consolidation.