Segment Reporting - Summarized Financial Information for Company's Reportable Segments (Parenthetical) (Detail) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Revenues		$ 135,388,000	$ 121,993,000	$ 339,807,000	$ 318,797,000
Enviroplex [Member]
Segment Reporting Information [Line Items]
Revenues	[1]			20,692,000	15,787,000
Mobile Modular [Member]
Segment Reporting Information [Line Items]
Revenues				173,828,000	158,452,000
Operating Segments [Member] | Enviroplex [Member]
Segment Reporting Information [Line Items]
Revenues				20,692,000	15,872,000
Inter-segment Eliminations [Member] | Mobile Modular [Member]
Segment Reporting Information [Line Items]
Sales revenues				$ 0	$ 85,000

[1] Gross Enviroplex sales revenues were $20,692 and $15,872 for the nine months ended September 30, 2017 and 2016, respectively, with no intercompany sales to Mobile Modular in 2017 and $85 inter-segment sales to Mobile Modular in 2016, which were eliminated in consolidation.