McGrath RentCorp (MGRC) 10-K 23 Feb 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 22, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Trading Symbol	MGRC
Entity Registrant Name	McGRATH RENTCORP
Security Exchange Name	NASDAQ
Title of 12(b) Security	Common Stock
Entity Interactive Data Current	Yes
Entity File Number	000-13292
Entity Incorporation, State or Country Code	CA
Entity Tax Identification Number	94-2579843
Entity Address, Address Line One	5700 Las Positas Road
Entity Address, City or Town	Livermore
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94551-7800
City Area Code	925
Local Phone Number	606-9200
Document Annual Report	true
Document Transition Report	false
Entity Central Index Key	0000752714
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Common Stock, Shares Outstanding		24,128,208
Entity Public Float			$ 1,287,170,749
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE McGrath RentCorp’s definitive proxy statement with respect to its 2021 Annual Meeting of Shareholders to be held on June 9, 2021 which will be filed with the Securities and Exchange Commission within 120 days after the end of its fiscal year ended December 31, 2020, is incorporated by reference into Part III (Items 10, 11, 12, and 13).

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Assets
Cash	$ 1,238	$ 2,342
Accounts receivable, net of allowance for doubtful accounts of $2,100 in 2020 and $1,883 in 2019	123,316	128,099
Rental equipment, at cost:
Relocatable modular buildings	882,115	868,807
Electronic test equipment	333,020	335,343
Liquid and solid containment tanks and boxes	315,706	316,261
Rental equipment, gross	1,530,841	1,520,411
Less accumulated depreciation	(592,725)	(552,911)
Rental equipment, net	938,116	967,500
Property, plant and equipment, net	136,210	131,047
Prepaid expenses and other assets	41,549	45,356
Intangible assets, net	7,118	7,334
Goodwill	28,197	28,197
Total assets	1,275,744	1,309,875
Liabilities:
Notes payable	222,754	293,431
Accounts payable and accrued liabilities	108,334	109,174
Deferred income	45,975	54,964
Deferred income taxes, net	216,077	218,270
Total liabilities	593,140	675,839
Shareholders’ equity:
Common stock, no par value - Authorized 40,000 shares Issued and outstanding - 24,296 shares as of December 31, 2019 and 24,182 shares as of December 31, 2018	106,289	106,360
Retained earnings	576,419	527,746
Accumulated other comprehensive loss	(104)	(70)
Total shareholders’ equity	682,604	634,036
Total liabilities and shareholders’ equity	$ 1,275,744	$ 1,309,875

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 2,100	$ 1,883
Common stock, par value
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	24,128,000	24,296,000
Common Stock, shares outstanding	24,128,000	24,296,000

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues
Rental	$ 351,790	$ 353,889	$ 318,774
Rental related services	92,393	101,038	82,907
Rental operations	444,183	454,927	401,681
Revenues	128,371	115,303	96,649
Total revenues	572,554	570,230	498,330
Direct costs of rental operations:
Depreciation of rental equipment	85,866	80,391	73,139
Rental related services	68,105	76,241	64,298
Other	73,818	79,365	68,678
Total direct costs of rental operations	227,789	235,997	206,115
Costs of sales	81,019	68,068	58,964
Total costs of revenues	308,808	304,065	265,079
Gross profit	263,746	266,165	233,251
Selling and administrative expenses	122,993	124,793	115,770
Income from operations	140,753	141,372	117,481
Other income (expense):
Interest expense	(8,787)	(12,331)	(12,297)
Foreign currency exchange gain	78	84	(489)
Income before provision for income taxes	132,044	129,125	104,695
Provision for income taxes	30,060	32,319	25,289
Net income	$ 101,984	$ 96,806	$ 79,406
Earnings per share:
Basic	$ 4.22	$ 3.99	$ 3.29
Diluted	$ 4.16	$ 3.93	$ 3.24
Shares used in per share calculation:
Basic	24,157	24,250	24,141
Diluted	24,531	24,623	24,540
Cash dividends declared per share	$ 1.68	$ 1.50	$ 1.36
Sales [Member]
Revenues
Revenues	$ 124,604	$ 110,229	$ 92,618
Other [Member]
Revenues
Revenues	$ 3,767	$ 5,074	$ 4,031

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 101,984	$ 96,806	$ 79,406
Other comprehensive income (loss):
Foreign currency translation adjustment	(48)	(29)	161
Tax benefit (provision)	14	8	(42)
Comprehensive income	$ 101,950	$ 96,785	$ 79,525

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2017	$ 524,184	$ 102,947	$ 421,405	$ (168)
Balance, Shares at Dec. 31, 2017		24,052,000
Net income	79,406		79,406
Share-based compensation	4,111	$ 4,111
Common stock issued under stock Plans, net of shares withheld for employee taxes, Shares		130,000
Taxes paid related to net share settlement of stock awards	(3,257)	$ (3,257)
Dividends accrued at $1.36, $1.50 and $1.68 per share in 2018, 2019 and 2020	(33,028)		(33,028)
Other comprehensive (loss) gain	119			119
Balance at Dec. 31, 2018	571,535	$ 103,801	467,783	(49)
Balance, Shares at Dec. 31, 2018		24,182,000
Net income	18,449
Balance at Mar. 31, 2019	580,643
Balance at Dec. 31, 2018	571,535	$ 103,801	467,783	(49)
Balance, Shares at Dec. 31, 2018		24,182,000
Net income	96,806		96,806
Share-based compensation	5,892	$ 5,892
Common stock issued under stock Plans, net of shares withheld for employee taxes, Shares		114,000
Taxes paid related to net share settlement of stock awards	(3,333)	$ (3,333)
Dividends accrued at $1.36, $1.50 and $1.68 per share in 2018, 2019 and 2020	(36,843)		(36,843)
Other comprehensive (loss) gain	(21)			(21)
Balance at Dec. 31, 2019	$ 634,036	$ 106,360	527,746	(70)
Balance, Shares at Dec. 31, 2019	24,296,000	24,296,000
Balance at Mar. 31, 2019	$ 580,643
Net income	19,488
Balance at Jun. 30, 2019	592,309
Net income	32,468
Balance at Sep. 30, 2019	616,715
Net income	26,401
Balance at Dec. 31, 2019	$ 634,036	$ 106,360	527,746	(70)
Balance, Shares at Dec. 31, 2019	24,296,000	24,296,000
Net income	$ 20,159
Balance at Mar. 31, 2020	637,604
Balance at Dec. 31, 2019	$ 634,036	$ 106,360	527,746	(70)
Balance, Shares at Dec. 31, 2019	24,296,000	24,296,000
Net income	$ 101,984		101,984
Share-based compensation	5,549	$ 5,549
Common stock issued under stock Plans, net of shares withheld for employee taxes, Shares		114,000
Repurchased common stock	(13,617)	$ (1,244)	(12,373)
Repurchased common stock, Shares		(282,000)
Taxes paid related to net share settlement of stock awards	(4,376)	$ (4,376)
Dividends accrued at $1.36, $1.50 and $1.68 per share in 2018, 2019 and 2020	(40,938)		(40,938)
Other comprehensive (loss) gain	(34)			(34)
Balance at Dec. 31, 2020	$ 682,604	$ 106,289	576,419	(104)
Balance, Shares at Dec. 31, 2020	24,128,000	24,128,000
Balance at Mar. 31, 2020	$ 637,604
Net income	22,549
Balance at Jun. 30, 2020	643,836
Net income	28,101
Balance at Sep. 30, 2020	661,614
Net income	31,175
Balance at Dec. 31, 2020	$ 682,604	$ 106,289	$ 576,419	$ (104)
Balance, Shares at Dec. 31, 2020	24,128,000	24,128,000

Consolidated Statements of Sh_2

Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash dividends declared per share	$ 1.68	$ 1.50	$ 1.36
Retained Earnings [Member]
Cash dividends declared per share	$ 1.68	$ 1.50	$ 1.36

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flows from Operating Activities:
Net income	$ 101,984,000	$ 96,806,000	$ 79,406,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	94,643,000	89,476,000	81,975,000
Impairment of rental assets	0	0	39,000
Provision for doubtful accounts	1,343,000	1,013,000	581,000
Share-based compensation	5,549,000	5,892,000	4,111,000
Gain on sale of used rental equipment	(19,329,000)	(21,309,000)	(19,559,000)
Foreign currency exchange (gain) loss	(78,000)	(84,000)	489,000
Amortization of debt issuance costs	11,000	11,000	20,000
Change in:
Accounts receivable	3,440,000	(7,323,000)	(15,725,000)
Prepaid expenses and other assets	3,807,000	(13,530,000)	(9,351,000)
Accounts payable and accrued liabilities	316,000	20,298,000	(1,612,000)
Deferred income	(8,989,000)	5,138,000	10,258,000
Deferred income taxes	(2,193,000)	11,606,000	12,035,000
Net cash provided by operating activities	180,504,000	187,994,000	142,667,000
Cash Flows from Investing Activities:
Purchases of rental equipment	(86,329,000)	(167,703,000)	(123,071,000)
Purchases of property, plant and equipment	(13,724,000)	(12,080,000)	(15,664,000)
Cash paid for acquisition of business assets		(7,808,000)	(7,543,000)
Proceeds from sales of used rental equipment	47,052,000	44,447,000	41,786,000
Net cash used in investing activities	(53,001,000)	(143,144,000)	(104,492,000)
Cash Flows from Financing Activities:
Net (repayment) borrowing under bank lines of credit	(70,689,000)	(5,144,000)	15,130,000
Principal payments on Series A senior notes			(20,000,000)
Repurchase of common stock	(13,617,000)
Taxes paid related to net share settlement of stock awards	(4,376,000)	(3,333,000)	(3,257,000)
Payment of dividends	(39,769,000)	(35,539,000)	(30,939,000)
Net cash used in financing activities	(128,451,000)	(44,016,000)	(39,066,000)
Effect of foreign currency exchange rate changes on cash	(156,000)		(102,000)
Net (decrease) increase in cash	(1,104,000)	834,000	(993,000)
Cash balance, beginning of period	2,342,000	1,508,000	2,501,000
Cash balance, end of period	1,238,000	2,342,000	1,508,000
Supplemental Disclosure of Cash Flow Information:
Interest paid, during the period	9,050,000	12,475,000	12,598,000
Net income taxes paid, during the period	34,903,000	17,528,000	18,157,000
Dividends accrued during the period, not yet paid	10,083,000	9,489,000	8,388,000
Rental equipment acquisitions, not yet paid	$ 4,373,000	$ 6,496,000	$ 9,695,000

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	NOTE 1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Organization McGrath RentCorp and its wholly-owned subsidiaries (the “Company”) is a California corporation organized in 1979. The Company is a diversified business to business rental company with four rental divisions; relocatable modular buildings, portable storage containers, electronic test equipment and liquid and solid containment tanks and boxes. Although the Company’s primary emphasis is on equipment rentals, sales of equipment occur in the normal course of business. The Company is comprised of four reportable business segments: modular building and portable storage segment (“Mobile Modular”), electronic test equipment segment (“TRS-RenTelco”), containment solutions for the storage of hazardous and non-hazardous liquids and solids segment (“Adler Tanks”) and classroom manufacturing division selling modular classrooms in California (“Enviroplex”). Principles of Consolidation The consolidated financial statements include the accounts of McGrath RentCorp and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Revenue Recognition Lease revenues - Rental revenues from operating leases are recognized on a straight-line basis over the term of the lease for all operating segments. Rental billings for periods extending beyond period end are recorded as deferred income and are recognized in the period earned. Rental related services revenues are primarily associated with relocatable modular building and liquid and solid containment tanks and boxes leases. For modular building leases, rental related services revenues for modifications, delivery, installation, dismantle and return delivery are lease related because the payments are considered minimum lease payments that are an integral part of the negotiated lease agreement with the customer. These revenues are recognized on a straight-line basis over the term of the lease. Certain leases are accounted for as sales-type leases. For these leases, sales revenue and the related accounts receivable are recognized upon delivery and installation of the equipment and the unearned interest is recognized over the lease term on a basis which results in a constant rate of return on the unrecovered lease investment. Other revenues include interest income on sales-type leases and rental income on facility leases. Non-lease revenues - Sales revenue is recognized upon delivery and installation of the equipment to customers. Certain leases are accounted for as sales-type leases. For these leases, sales revenue and the related accounts receivable are recognized upon delivery and installation of the equipment and the unearned interest is recognized over the lease term on a basis which results in a constant rate of return on the unrecovered lease investment. Other revenue is recognized when earned and primarily includes interest income on sales-type leases, rental income on facility leases and certain logistics services. Sales taxes charged to customers are reported on a net basis and are excluded from revenues and expenses. Depreciation of Rental Equipment Rental equipment is depreciated on a straight-line basis for financial reporting purposes and on an accelerated basis for income tax purposes. The costs of major refurbishment of relocatable modular buildings, portable storage containers and tanks and boxes are capitalized to the extent the refurbishment significantly adds value to, or extends the life of the equipment. Maintenance and repairs are expensed as incurred. The estimated useful lives and residual values of the Company’s rental equipment used for financial reporting purposes are as follows: Relocatable modular buildings 18 years, 50% residual value Relocatable modular accessories 3 to 18 years, no residual value Blast resistant modules 20 years, no residual value Portable storage containers 25 years, 62.5% residual value Electronic test equipment and accessories 1 to 8 years, no residual value Liquid and solid containment tanks and boxes and accessories 3 to 20 years, no residual value Costs of Rental Related Services Costs of rental related services are primarily associated with relocatable modular building leases and liquid and solid containment tank and boxes. Modular building leases primarily consist of costs for services to be provided under the negotiated lease agreement for delivery, installation, modifications, skirting, additional site-related work, and dismantle and return delivery. Costs related to these services are recognized on a straight-line basis over the term of the lease. Costs of rental related services associated with liquid and solid containment solutions consists of costs of delivery, removal and cleaning of the tanks and boxes. These costs are recognized in the period the service is performed. Impairment of Long-Lived Assets The Company evaluates the carrying value of rental equipment and identifiable definite lived intangible assets for impairment whenever events or circumstances have occurred that would indicate the carrying amount may not be fully recoverable. A key element in determining the recoverability of long-lived assets is the Company’s outlook as to the future market conditions for its rental equipment. If the carrying amount is not fully recoverable, an impairment loss is recognized to reduce the carrying amount to fair value. The Company determines fair value based upon the condition of the rental equipment and the projected net cash flows from its rental and sale considering current market conditions. Goodwill and identifiable indefinite lived assets are evaluated for potential impairment annually or when circumstances indicate potential impairment may have occurred. Impairment losses, if any, are determined based upon the excess of carrying value over the estimated fair value of the asset. There were no impairments of long-lived assets during the years ended December 31, 2020 and 2019. The Company recorded an impairment of modular rental equipment of $0.1 million for the year ended December 31, 2018. Other Direct Costs of Rental Operations Other direct costs of rental operations include direct labor, supplies, repairs, insurance, property taxes, license fees, impairment of rental equipment and certain modular lease costs charged to customers in the negotiated rental rate, which are recognized on a straight-line basis over the term of the lease. Cost of Sales Cost of sales in the Consolidated Statements of Income includes the carrying value of the equipment sold and all direct costs associated with the sale. Warranty Reserves Sales of new relocatable modular buildings, portable storage containers, electronic test equipment and related accessories and liquid and solid containment tanks and boxes not manufactured by the Company are typically covered by warranties provided by the manufacturer of the products sold. The Company typically provides limited 90-day warranties for certain sales of used rental equipment and one-year Property, Plant and Equipment Property, plant and equipment are stated at cost, net of accumulated depreciation. Depreciation is recognized on a straight-line basis for financial reporting purposes, and on an accelerated basis for income tax purposes. Depreciation expense for property, plant and equipment is included in “Selling and administrative expenses” and “Rental related services” in the Consolidated Statements of Income. Maintenance and repairs are expensed as incurred. Property, plant and equipment consist of the following: (dollar amounts in thousands) Estimated useful life December 31, in years 2020 2019 Land Indefinite $ 54,429 $ 54,423 Land improvements 20 – 50 59,249 52,325 Buildings 30 32,306 29,848 Furniture, office equipment and software 3 – 10 36,882 36,610 Vehicles and machinery 5 – 25 43,101 41,877 225,967 215,083 Less accumulated depreciation (91,514 ) (84,308 ) 134,453 130,775 Construction in progress 1,757 272 $ 136,210 $ 131,047 Property, plant and equipment depreciation expense was $8.6 million, $8.2 million and $8.0 million for the years ended December 31, 2020, 2019 and 2018, respectively. Construction in progress at December 31, 2020 and 2019 consisted primarily of costs related to acquisition of land, land improvements and information technology upgrades. Capitalized Software Costs The Company capitalizes certain development costs incurred in connection with its internal use software. Costs incurred in the preliminary stages of development are expensed as incurred. Once an application has reached the development stage, direct internal and external costs are capitalized until the software is substantially complete and ready for its intended use. These costs generally include external direct costs of materials and services consumed in the project and internal costs, such as payroll and benefits of those employees directly associated with the development of the software. Maintenance, training and post implementation costs are expensed as incurred. The Company also capitalizes costs related to specific upgrades and enhancements when it is probable the expenditures will result in additional functionality. Capitalized software costs are included in property, plant and equipment. The Company capitalized $0.1 million and $3.0 million in internal use software during the years ended December 31, 2020 and 2019, respectively. Advertising Costs Advertising costs are expensed as incurred. Total advertising expenses were $3.9 million, $3.6 million and $3.2 million for the years ended December 31, 2020, 2019 and 2018. Income Taxes Income taxes are accounted for using an asset and liability approach. Deferred tax assets and liabilities are recorded for the effect of temporary differences between the tax basis of assets and liabilities and their reported amounts in the consolidated financial statements. Deferred tax assets and deferred tax liabilities are adjusted to the extent necessary to reflect tax rates expected to be in effect when temporary differences reverse. Adjustments may be required to deferred tax assets and deferred tax liabilities due to changes in tax laws and audit adjustments by tax authorities. A valuation allowance would be established if, based on the weight of available evidence, management believes that it is more likely than not that some portion or all of a recorded deferred tax asset would not be realized in future periods. To the extent adjustments are required in any given period, the adjustments would be included within the “Provision for income taxes” in the Consolidated Statements of Income. Goodwill and Intangible Assets Purchase prices of acquired businesses are allocated to the assets and liabilities acquired based on the estimated fair values on the respective acquisition dates. Based on these values, the excess purchase prices over the fair value of the net assets acquired are allocated to goodwill and other intangible assets. Intangible assets related to customer relationships are amortized over eleven years. At December 31, 2020 and 2019, goodwill and trade name intangible assets which have indefinite lives totaled $34.1 million. The Company assesses potential impairment of its goodwill and intangible assets when there is evidence that events or circumstances have occurred that would indicate the recovery of an asset’s carrying value is unlikely. The Company also assesses potential impairment of its goodwill and intangible assets with indefinite lives on an annual basis regardless of whether there is evidence of impairment. If indicators of impairment were to be present in intangible assets used in operations and future discounted cash flows were not expected to be sufficient to recover the assets’ carrying amount, an impairment loss would be charged to expense in the period identified. The amount of an impairment loss would be recognized as the excess of the asset’s carrying value over its fair value. Factors the Company considers important, which may cause impairment include, among others, significant changes in the manner of use of the acquired asset, negative industry or economic trends, and significant underperformance relative to historical or projected operating results. The impairment review of the Company’s goodwill is performed by first assessing qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. The fair value of the reporting unit is compared to its carrying value to determine if the goodwill is impaired. If the fair value of the reporting unit exceeds the carrying value of the net assets assigned to that unit, then goodwill is not impaired. If the carrying value of the net assets assigned to the reporting unit were to exceed its fair value, then a goodwill impairment loss is recorded for the amount the reporting unit’s carrying value exceeds the estimated fair value. The Company conducted its annual impairment analysis in the fourth quarter of 2020. The impairment analysis did not result in an impairment charge for the fiscal year ended 2020. There were no impairment charges in 2019 or 2018. Determining the fair value of a reporting unit is judgmental and involves the use of significant estimates and assumptions. The Company based its fair value estimates on assumptions that it believes are reasonable but are uncertain and subject to changes in market conditions. Earnings Per Share Basic earnings per share (“EPS”) is computed as net income divided by the weighted average number of shares of common stock outstanding for the period. Diluted EPS is computed assuming conversion of all potentially dilutive securities including the dilutive effects of stock options, unvested restricted stock awards and other potentially dilutive securities. The table below presents the weighted-average common stock used to calculate basic and diluted earnings per share: (in thousands) Year Ended December 31, 2020 2019 2018 Weighted-average common stock for calculating basic earnings per share 24,157 24,250 24,141 Effect of potentially dilutive securities from equity-based compensation 374 373 399 Weighted-average common stock for calculating diluted earnings per share 24,531 24,623 24,540 In 2020, 2019 and 2018, there were no shares having an anti-dilutive effect requiring exclusion from the computation of diluted earnings per share. The Company has made purchases of shares of its common stock from time to time in over-the-counter market (NASDAQ) transactions, through privately negotiated, large block transactions and through a share repurchase plan, in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934. In August 2015, the Company’s Board of Directors authorized the Company to repurchase up to 2,000,000 shares of the Company's outstanding common stock (the “Repurchase Plan”). The amount and time of the specific repurchases are subject to prevailing market conditions, applicable legal requirements and other factors, including management’s discretion. All shares repurchased by the Company are canceled and returned to the status of authorized but unissued shares of common stock. There can be no assurance that any authorized shares will be repurchased and the Repurchase Plan may be modified, extended or terminated by the Board of Directors at any time. In the twelve months ended December 31, 2020, the company repurchased 282,221 shares of its common stock for an average purchase price of $48.25 per share or an aggregate price of $13.6 million. There were no repurchases of common stock during the twelve months ended December 31, 2019 and 2018. As of December 31, 2020, 1,309,805 shares remain authorized for repurchase. Accounts Receivable and Concentration of Credit Risk The Company’s accounts receivable consist of amounts due from customers for rentals, sales, financed sales and unbilled amounts for the portion of modular building end-of-lease services earned, which were negotiated as part of the lease agreement. Unbilled receivables related to end-of-lease services, which consists of dismantle and return delivery of buildings, were $38.7 million at December 31, 2020 and $37.2 million at December 31, 2019. The Company sells primarily on 30-day terms, individually performs credit evaluation procedures on its customers on each transaction and will require security deposits from its customers when a significant credit risk is identified. The Company records an allowance for doubtful accounts in amounts equal to the estimated losses expected to be incurred in the collection of the accounts receivable. The estimated losses are based on historical collection experience in conjunction with an evaluation of the current status of the existing accounts. Customer accounts are written off against the allowance for doubtful accounts when an account is determined to be uncollectable. The allowance for doubtful accounts activity was as follows: (in thousands) 2020 2019 Beginning balance, January 1 $ 1,883 $ 1,883 Provision for doubtful accounts 1,343 1,013 Write-offs, net of recoveries (1,126 ) (1,013 ) Ending balance, December 31 $ 2,100 $ 1,883 Financial instruments that potentially subject the Company to concentration of credit risk consist primarily of trade accounts receivable. From time to time, the Company maintains cash balances in excess of the Federal Deposit Insurance Corporation limits. Fair Value of Financial Instruments The Company believes that the carrying amounts for cash, accounts receivable, accounts payable and notes payable approximate their fair values except for fixed rate debt included in notes payable which has an estimated fair value of $103.1 million and $101.4 million compared to the recorded value of $100.0 million as of December 31, 2020 and 2019, respectively. The estimates of fair value of the Company’s fixed rate debt are based on the borrowing rates currently available to the Company for bank loans with similar terms and average maturities. Foreign Currency Transactions and Translation The Company's Canadian subsidiary, TRS-RenTelco Inc., a British Columbia corporation (“TRS-Canada”), functions as a branch sales office for TRS-RenTelco in Canada. The functional currency for TRS-Canada is the U.S. dollar. Foreign currency transaction gains and losses of TRS-Canada are reported in the results of operations in the period in which they occur. The Company’s Indian subsidiary, TRS-RenTelco India Private Limited (“TRS-India”), functioned as a rental and sales office for TRS-RenTelco in India, which commenced its closure during 2017. The functional currency for TRS-India is the Indian Rupee. All assets and liabilities of TRS-India are translated into U.S. dollars at period-end exchange rates and all income statement amounts are translated at the average exchange rate for each month within the year. Currently, the Company does not use derivative instruments to hedge its economic exposure with respect to assets, liabilities and firm commitments as the foreign currency transactions and risks to date have not been significant. Share-Based Compensation The Company measures and recognizes the compensation expense for all share-based awards made to employees and directors, including stock options, stock appreciation rights (“SARs”) and restricted stock units (“RSUs”), based upon estimated fair values. The fair value of stock options and SARs is estimated on the date of grant using the Black-Scholes option pricing model and for RSUs based upon the fair market value of the underlying shares of common stock as of the date of grant. The Company recognizes share-based compensation cost ratably on a straight-line basis over the requisite service period, which generally equals the vesting period. For performance-based RSUs, compensation costs are recognized when vesting conditions are met. In addition, the Company estimates the probable number of shares of common stock that will be earned and the corresponding compensation cost until the achievement of the performance goal is known. Use of Estimates The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions in determining reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during each period presented. Actual results could differ from those estimates. The most significant estimates included in the financial statements are the future cash flows and fair values used to determine the recoverability of the rental equipment and identifiable definite lived intangible assets carrying value, the various assets’ useful lives and residual values, and the allowance for doubtful accounts.

New Accounting Pronouncements

New Accounting Pronouncements	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
New Accounting Pronouncements	NOTE 2. In December 2019, the FASB issued Accounting Standard Update (“ASU”) 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, expected to reduce cost and complexity related to the accounting for income taxes. The ASU removes specific exceptions to the general principles in Topic 740 in Generally Accepted Accounting Principles (GAAP). It eliminates the need for an organization to analyze whether the following apply in a given period: exception to the incremental approach for intra-period tax allocation; exceptions to accounting for basis differences when there are ownership changes in foreign investments; and exception in interim period income tax accounting for year-to-date losses that exceed anticipated losses. The ASU also improves financial statement preparers’ application of income tax-related guidance and simplifies GAAP for: franchise taxes that are partially based on income; transactions with a government that result in a step up in the tax basis of goodwill; separate financial statements of legal entities that are not subject to tax; and enacted changes in tax laws in interim periods. For public business entities, this ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. The Company does not expect the adoption of this ASU to have a material impact on its consolidated financial statements.

Implemented Accounting Pronounc

Implemented Accounting Pronouncements	12 Months Ended
	Dec. 31, 2020
Accounting Changes And Error Corrections [Abstract]
Implemented Accounting Pronouncements	NOTE 3. IMPLEMENTED ACCOUNTING PRONOUNCEMENTS Effective January 1, 2020, the Company adopted ASU 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment, intended to simplify the subsequent accounting for goodwill acquired in a business combination. Prior guidance required utilizing a two-step process to review goodwill for impairment. A second step was required if there was an indication that an impairment may exist, and the second step required calculating the potential impairment by comparing implied fair value of the reporting unit’s goodwill with the carrying amount of the goodwill. The new guidance eliminates the second step from the goodwill impairment test. Under the new guidance, an entity should perform its annual, or interim, goodwill impairment test by comparing the estimated fair value of a reporting unit with its carrying amount. An entity would recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit's estimated fair value. The adoption of this new guidance did not have a material impact on the Company’s condensed consolidated financial statements. The Company adopted ASU 2016-13, Financial Instruments – Credit Losses (Topic 326) effective January 1, 2020. Under the new guidance, companies are required to present financial assets held at amortized cost and available for sale debt securities net of the amount expected to be collected. The new guidance requires the measurement of expected credit losses to be based on relevant information from past events, including historical experiences, current conditions and reasonable and supportable forecasts that affect collectability. The adoption of this new guidance did not have a material impact on the Company’s condensed consolidated financial statements. Trade accounts receivable The allowance for doubtful accounts is based on the Company’s assessment of the collectability of customer accounts receivable from operating lease and non-lease revenues. The Company regularly reviews the allowance by considering factors such as historical payment experience and trends, the age of the accounts receivable balances, the Company’s operating segment, customer industry, credit quality and current economic conditions that may affect a customer’s ability to pay. The Company recognized bad debt expense of $1.3 million, $1.0 million and 0.6 million for the twelve months ended December 31, 2020, 2019 and 2018, respectively. The allowance for doubtful accounts was $2.1 million, $1.9 million and $1.9 million at December 31, 2020, 2019 and 2018, respectively. Net investment in sales-type leases The Company enters into sales-type leases with certain qualified customers to purchase its rental equipment, primarily at its TRS-RenTelco operating segment. Sales-type leases have terms that generally range from 12 to 36 months and are collateralized by a security interest in the underlying rental asset. The net investment in sales-type leases was $1.8 million at December 31, 2020 and $2.9 million at December 31, 2019. The Company’s assessment of current expected losses on these receivables was not material and no credit loss expense was provided as of December 31, 2020. The Company regularly reviews the allowance by considering factors such as historical payment experience, the age of the lease receivable balances, credit quality and current economic conditions that may affect a customer's ability to pay. Lease receivables are considered past due 90 days after invoice. The Company manages the credit risk in net investment in sales-type leases, on an ongoing basis, using a number of factors, including, but not limited to the following: historical payment history, credit score, size of operations, length of time in business, industry, historical profitability, historical cash flows, liquidity and past due amounts. The Company uses credit scores obtained from external credit bureaus as a key indicator for the purposes of determining credit quality of its new customers. The Company does not own available for sale debt securities or other financial assets at December 31, 2020.

Leases

Leases	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leases	NOTE 4. LEASES Lessee The Company leases real estate for certain of its branch offices and rental equipment storage yards, vehicles and equipment used in its rental operations. The Company determines if an arrangement is a lease at inception. The Company has leases with lease and non-lease components, which are accounted for separately. Right-Of-Use (“ROU”) assets and liabilities are recognized on the commencement date based on the present value of lease payments over the lease term. Variable lease payments are excluded from the ROU assets and lease liabilities and are recognized in the period in which the obligation for those payments is incurred, which are not material. The Company’s lease agreements do not contain any material residual value guarantees or material restrictive covenants. The Company uses the interest rate stated in the lease as the discount rate. If the interest rate is not stated, the Company uses its incremental borrowing rate based on information available on lease commencement date in determining the present value of lease payments. Many of the Company’s real estate lease agreements include options to extend the lease, which are not included in the minimum lease terms unless they are reasonably certain to be exercised. These leases include one or more options to renew, with renewal terms that may extend the lease term from one to three years. The amount of payments associated with such options is not material. Short-term leases are leases having a term of twelve months or less and exclude leases with a lease term of one month or less. The Company recognizes short-term leases on a straight-line basis and does not record a related ROU asset or liability for such leases. At December 31, 2020 and 2019 the Company’s ROU assets and operating lease liabilities was $8.3 million and $9.9 During the year ended December 31, 2020, operating lease expense was $3.8 million, which includes short term lease expense of $0.1 million. At December 31, 2020, the weighted-average remaining lease term for operating leases was 3.2 years and the weighted average discount rate was 3.95%. The Company had no sub-lease income during the year ended December 31, 2020, and did not have any finance leases as of December 31, 2020. Supplemental cash flow information related to leases was as follows: (in thousands) Year Ended December 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 3,683 $ 3,568 Right of use assets obtained in exchange for lease obligations: Operating leases $ 1,885 $ 2,728 As of December 31, 2020, maturities of operating lease liabilities were as follows: (in thousands) Year ended December 31, 2021 $ 3,294 2022 2,372 2023 1,756 2024 1,066 2025 293 Thereafter — Total lease payments 8,781 Less imputed interest (494 ) $ 8,287 Lessor The Company’s equipment rentals for each of its operating segments are governed by agreements that detail the lease terms and conditions. The determination of whether these contracts with customers contain a lease generally does not require significant judgement. The Company accounts for these rentals as operating leases. These leases do not include material amounts of variable payments and the Company has made the accounting policy election to exclude all taxes assessed by a governmental authority. The Company generally does not provide an option for the lessee to purchase the rented equipment at the end of the lease term, thus, does not generate material revenue from sales of equipment under such options. Initial lease terms vary in length based upon customer needs and generally range from one to sixty months. Customers have the option to keep equipment on rent beyond the initial lease term on a month-to month basis based upon their needs. All of the Company’s rental products have long useful lives relative to the typical rental term with the original investment typically recovered in approximately three to five years. The rental products are typically rented for a majority of the time owned and a significant portion of the original investment is recovered when sold from inventory. The Company’s lease agreements do not contain residual value guarantees or restrictive covenants. As of December 31, 2020, maturities of operating lease payments to be received in 2021 and thereafter were as follows: (in thousands) Year Ended December 31, 2021 $ 83,482 2022 24,208 2023 7,680 2024 2,741 2025 542 Thereafter 10 $ 118,663 In the year ended December 31, 2020, the Company’s lease revenues were $401.9 million, consisting of $399.5 of operating lease revenues and $2.4 million of finance lease revenues. The Company has entered into finance leases to finance certain equipment sales to customers. The lease agreements have a bargain purchase option at the end of the lease term. For these leases, sales revenue and the related accounts receivable are recognized upon delivery and installation of the equipment and the unearned interest is recognized over the lease term on a basis, which results in a constant rate of return on the unrecovered lease investment. For the year ended December 31, 2020, the Company’s finance lease revenues included $2.2 million of sales revenues and $0.2 million of interest income. The minimum lease payments receivable and the net investment are included in Accounts receivable on the Company’s Consolidated Balance Sheet for such leases, which were as follows: (in thousands) December 31, 2020 Gross minimum lease payments receivable $ 1,953 Less – unearned interest (166 ) Net investment in finance lease receivables $ 1,787 As of December 31, 2020, the future minimum lease payments under non-cancelable finance leases to be received in 2021 and thereafter were as follows: (in thousands) Year Ended December 31, 2021 $ 1,463 2022 267 2023 49 2024 8 Thereafter — Total minimum future lease payments to be received $ 1,787

Revenue Recognition

Revenue Recognition	12 Months Ended
	Dec. 31, 2020
Revenue From Contract With Customer [Abstract]
Revenue Recognition	NOTE 5. REVENUE RECOGNITION The Company’s accounting for revenues is governed by two accounting standards. The majority of the Company’s revenues are considered lease or lease related and are accounted for in accordance with Topic 840, Leases. Revenues determined to be non-lease related are accounted for in accordance with ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), which was adopted by the Company on January 1, 2018. The Company utilized the modified retrospective method of adoption and there was no impact on its condensed consolidated financial statements, nor was there a cumulative effect of initially applying the new standard. The Company accounts for revenues when approval and commitment from both parties have been obtained, the rights of the parties are identified, payment terms are identified, the contract has commercial substance and collectability of consideration is probable. The Company typically recognizes non-lease related revenues at a point in time because the customer does not simultaneously consume the benefits of the Company’s promised goods and services, or performance obligations, and obtain control when delivery and installation are complete. For contracts that have multiple performance obligations, the transaction price is allocated to each performance obligation in the contract based on the Company’s best estimate of the standalone selling prices of each distinct performance obligation in the contract. The standalone selling price is typically determined based upon the expected cost plus an estimated margin of each performance obligation. The Company generally rents and sells to customers on 30 day payment terms. The Company does not typically offer variable payment terms, or accept non-monetary consideration. Amounts billed and due from the Company’s customers are classified as Accounts receivable on the Company’s consolidated balance sheet. For certain sales of modular buildings, progress payments from the customer are received during the manufacturing of new equipment, or the preparation of used equipment. The advance payments are not considered a significant financing component because the payments are used to meet working capital needs during the contract and to protect the Company from the customer failing to adequately complete their obligations under the contract. These contract liabilities are included in Deferred income on the Company’s consolidated balance sheets and totaled $11.3 million and $17.5 million at December 31, 2020 and 2019, respectively. Sales revenues totaling $17.0 million were recognized during the year ended December 31, 2020, which were included in the contract liability balance at December 31, 2019. For certain modular building sales, the customer retains a small portion of the contract price until full completion of the contract, which results in revenue earned in excess of billings. These unbilled contract assets are included in Accounts receivable on the Company’s consolidated balance sheets and totaled $1.4 million and $1.0 million at December 31, 2020 and 2019, respectively. Lease Revenues Rental revenues from operating leases are recognized on a straight-line basis over the term of the lease for all operating segments. Rental billings for periods extending beyond period end are recorded as deferred income and are recognized in the period earned. Rental related services revenues are primarily associated with relocatable modular building and liquid and solid containment tanks and boxes leases. For modular building leases, rental related services revenues for modifications, delivery, installation, dismantle and return delivery are lease related because the payments are considered minimum lease payments that are an integral part of the negotiated lease agreement with the customer. These revenues are recognized on a straight-line basis over the term of the lease. Certain leases are accounted for as sales-type leases. For these leases, sales revenue and the related accounts receivable are recognized upon delivery and installation of the equipment and the unearned interest is recognized over the lease term on a basis which results in a constant rate of return on the unrecovered lease investment. Other revenues include interest income on sales-type leases and rental income on facility leases. Non-Lease Revenues Non-lease revenues are recognized in the period when control of the performance obligation is transferred, in an amount that reflects the consideration the Company expects to be entitled to receive in exchange for those goods or services. For liquid and solid containment solutions, portable storage containers and electronic test equipment, rental related services revenues for delivery and return delivery are considered non-lease revenues. Sales revenues are typically recognized at a point in time, which occurs upon the completion of delivery, installation and acceptance of the equipment by the customer. Accounting for non-lease revenues requires judgment in determining the point in time the customer gains control of the equipment and the appropriate accounting period to recognize revenue. Sales taxes charged to customers are reported on a net basis and are excluded from revenues and expenses. The following table disaggregates the Company’s revenues by lease (within the scope of Topic 840) and non-lease revenues (within the scope of Topic 606) and the underlying service provided for the three years ended December 31, 2020, 2019 and 2018: (in thousands) Mobile Modular TRS- RenTelco Adler Tanks Enviroplex Consolidated Year Ended December 31, 2020 Leasing $ 235,003 $ 112,210 $ 54,710 $ — $ 401,923 Non-lease: Rental related services 22,576 2,618 21,320 — 46,514 Sales 63,863 24,461 1,386 32,737 122,447 Other 82 1,522 66 — 1,670 Total non-lease 86,521 28,601 22,772 32,737 170,631 Total revenues $ 321,524 $ 140,811 $ 77,482 $ 32,737 $ 572,554 2019 Leasing $ 234,032 $ 108,044 $ 68,917 $ — $ 410,993 Non-lease: Rental related services 18,964 2,599 27,634 — 49,197 Sales 47,045 18,995 1,266 39,814 107,120 Other 969 1,845 106 — 2,920 Total non-lease 66,978 23,439 29,006 39,814 159,237 Total revenues $ 301,010 $ 131,483 $ 97,923 $ 39,814 $ 570,230 2018 Leasing $ 200,214 $ 94,345 $ 70,653 $ — $ 365,212 Non-lease: Rental related services 14,870 2,607 24,276 — 41,753 Sales 39,467 19,895 1,044 29,046 89,452 Other 23 1,810 80 — 1,913 Total non-lease 54,360 24,312 25,400 29,046 133,118 Total revenues $ 254,574 $ 118,657 $ 96,053 $ 29,046 $ 498,330 Customer returns of rental equipment prior to the end of the rental contract term are typically billed a cancellation fee, which is recorded as rental revenue in the period billed. Sales of new relocatable modular buildings, portable storage containers, electronic test equipment and related accessories and liquid and solid containment tanks and boxes not manufactured by the Company are typically covered by warranties provided by the manufacturer of the products sold. The Company typically provides limited 90-day warranties for certain sales of used rental equipment and one-year The Company’s incremental cost of obtaining lease contracts, which consists of salesperson commissions, are deferred and amortized over the initial lease term for modular building leases. Incremental costs for obtaining a contract for all other operating segments are expensed in the period incurred because the lease term is typically less than 12 months.

Notes Payable

Notes Payable	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Notes Payable	NOTE 6. NOTES PAYABLE Notes payable consists of the following: (in thousands) December 31, 2020 2019 Unsecured revolving lines of credit $ 122,771 $ 193,459 3.68% Series B senior notes due in 2021 40,000 40,000 3.84% Series C senior notes due in 2022 60,000 60,000 222,771 293,459 Unamortized debt issuance cost (17 ) (28 ) $ 222,754 $ 293,431 As of December 31, 2020, the future minimum payments under the unsecured revolving lines of credit, 3.68% Series B senior notes due in 2021 and 3.84% Series C senior notes due in 2022 are as follows: (in thousands) Year Ended December 31, 2021 $ 40,000 2022 60,000 2023 — 2024 — 2025 122,771 $ 222,771 Unsecured Revolving Lines of Credit On March 31, 2020, the Company entered into an amended and restated credit agreement with Bank of America, N.A., as Administrative Agent, Swing Line Lender, L/C Issuer and lender, and other lenders named therein (the “Credit Facility”). The Credit Facility provides for a $420.0 million unsecured revolving credit facility (which may be further increased to $670.0 million by adding one or more tranches of term loans and/or increasing the aggregate revolving commitments), which includes a $25.0 million sublimit for the issuance of standby letters of credit and a $10.0 million sublimit for swingline loans. The proceeds of the Credit Facility are available to be used for general corporate purposes, including permitted acquisitions. The Credit Facility permits the Company’s existing indebtedness to remain, which includes the Company’s $12.0 million Treasury Sweep Note due March 31, 2025, the Company’s existing senior notes issued pursuant to the Note Purchase and Private Shelf Agreement with Prudential Investment Management, Inc., dated as of April 21, 2011 (as amended, the “the Prior NPA”): (i) the $40.0 million aggregate outstanding principal of notes issued March 17, 2014 and due March 17, 2021, and (ii) the $60.0 million aggregate outstanding principal of notes issued November 5, 2015 and due November 5, 2022. In addition, the Company may incur additional senior note indebtedness in an aggregate amount not to exceed $250.0 million. The Credit Facility matures on March 31, 2025 and replaced the Company’s prior $420.0 million credit facility dated March 31, 2016 with Bank of America, N.A., as agent, as amended. All obligations outstanding under the prior credit facility as of the date of the Credit Facility were refinanced by the Credit Facility on March 31, 2020. On March 31, 2020, the Company entered into an amended and restated Credit Facility Letter Agreement and a Credit Line Note in favor of MUFG Union Bank, N.A., which provides for a $12.0 million line of credit facility related to its cash management services (“Sweep Service Facility”). The Sweep Service Facility matures on the earlier of March 31, 2025, or the date the Company ceases to utilize MUFG Union Bank, N.A. for its cash management services. The Sweep Service Facility replaced the Company’s prior $12.0 million sweep service facility, dated as of March 31, 2016. At December 31, 2020, under the Credit Facility and Sweep Service Facility, the Company had unsecured lines of credit that permit it to borrow up to $432.0 million of which $122.8 million was outstanding. The Amended Credit Facility contains financial covenants requiring the Company to not (all defined terms used below not otherwise defined herein have the meaning assigned to such terms in the Amended Credit Facility): • Permit the Consolidated Fixed Charge Coverage Ratio of EBITDA to fixed charges as of the end of any fiscal quarter to be less than 2.50 to 1. At December 31, 2020, the actual ratio was 4.34 to 1. • Permit the Consolidated Leverage Ratio of funded debt to EBITDA at any time during any period of four consecutive fiscal quarters to be greater than 2.75 to 1. At December 31, 2020, the actual ratio was 0.92 to 1. Amounts borrowed under the Credit Facility bear interest at the Company’s option at either: (i) LIBOR plus a defined margin, or (ii) the Agent bank’s prime rate (“base rate”) plus a margin. The applicable margin for each type of loan is measured based upon the Consolidated Leverage Ratio at the end of the prior fiscal quarter and ranges from 1.00% to 1.75% for LIBOR loans and 0% to 0.75% for base rate loans. In addition, the Company pays an unused commitment fee for the portion of the $420.0 million credit facility that is not used. These fees are based upon the Consolidated Leverage Ratio and range from 0.15% to 0.30%. As of December 31, 2020 and 2019, the applicable margins were 1.25% for LIBOR based loans, 0.25% for base rate loans and 0.20% for unused fees. Amounts borrowed under the Sweep Service Facility are based upon the MUFG Union Bank, N.A. base rate plus an applicable margin and an unused commitment fee for the portion of the $12.0 million facility not used. The applicable base rate margin and unused commitment fee rates for the Sweep Service Facility are the same as for the Amended Credit Facility. The following information relates to the lines of credit for each of the following periods: (dollar amounts in thousands) Year Ended December 31, 2020 2019 Maximum amount outstanding $ 199,471 $ 219,635 Average amount outstanding $ 170,075 $ 201,195 Weighted average interest rate, during the period 2.11 % 3.59 % Prime interest rate, end of period 3.25 % 4.75 % Note Purchase and Private Shelf Agreement On March 31, 2020, the Company entered into an Amended and Restated Note Purchase and Private Shelf Agreement (the “Note Purchase Agreement”) with PGIM, Inc. (“PGIM”) and the holders of Series B and Series C Notes previously issued pursuant to the Prior NPA, among the Company and the other parties to the Note Purchase Agreement. The Note Purchase Agreement amended and restated, and superseded in its entirety, the Prior NPA. Pursuant to the Prior NPA, the Company issued (i) $40.0 million aggregate principal amount of its 3.68% Series B Senior Notes due March 17, 2021, and (ii) $60.0 million aggregate principal amount of its 3.84% Series C Senior Notes due November 5, 2022, to which the terms of the Note Purchase Agreement shall apply. In addition, pursuant to the Note Purchase Agreement, the Company may authorize the issuance and sale of additional senior notes (the “Shelf Notes”) in the aggregate principal amount of (x) $250 million minus (y) the amount of other notes (such as the Series B Senior Notes and Series C Senior Notes, each defined below) then outstanding, to be dated the date of issuance thereof, to mature, in case of each Shelf Note so issued, no more than 15 years after the date of original issuance thereof, to have an average life, in the case of each Shelf Note so issued, of no more than 15 years after the date of original issuance thereof, to bear interest on the unpaid balance thereof from the date thereof at the rate per annum, and to have such other particular terms, as shall be set forth, in the case of each Shelf Note so issued, in accordance with the Note Purchase Agreement. On October 1, 2020, the Company entered into a rate lock agreement with Prudential Private Capital, pursuant to which, the Company agreed to a fixed interest rate of 2.57% for future issuance, if any, of senior unsecured notes in the aggregate amount of $40.0 million with a 7-year maturity. If issued, the funding for such notes would occur on or before March 17, 2021 and would be subject to the terms and conditions of the Note Purchase Agreement. 3.68% Senior Notes Due in 2021 On March 17, 2014, the Company issued and sold to the purchaser a $40.0 million aggregate principal amount of its 3.68% Series B Senior Notes (the “Series B Senior Notes”) pursuant to the terms of the Prior NPA. The Series B Senior Notes are an unsecured obligation of the Company and bear interest at a rate of 3.68% per annum and mature on March 17, 2021. Interest on the Series B Senior Notes is payable semi-annually beginning on September 17, 2014 and continuing thereafter on March 17 and September 17 of each year until maturity. The full net proceeds from the Series B Senior Notes were used for working capital and other general corporate purposes. At December 31, 2020, the principal balance outstanding under the Series B Senior Notes was $40.0 million. 3.84% Senior Notes Due in 2022 On November 5, 2015, the Company issued and sold to the purchaser a $60.0 million aggregate principal amount of its 3.84% Series C Senior Notes (the “Series C Senior Notes”) pursuant to the terms of the Prior NPA. The Series C Senior Notes are an unsecured obligation of the Company and bear interest at a rate of 3.84% per annum and mature on November 5, 2022. Interest on the Series C Senior Notes is payable semi-annually beginning on May 5, 2016 and continuing thereafter on November 5 and May 5 of each year until maturity. The principal balance is due when the notes mature on November 5, 2022. The full net proceeds from the Series C Senior Notes were used to reduce the outstanding balance on the Company’s revolving credit line. At December 31, 2020, the principal balance outstanding under the Series C Senior Notes was $ 60.0 million. Among other restrictions, the Note Purchase Agreement, under which the Series A Senior Notes, Series B Senior Notes and Series C Senior Notes were sold, contains financial covenants requiring the Company to not (all defined terms used below not otherwise defined herein have the meaning assigned to such terms in the Note Purchase Agreement): • Permit the Consolidated Fixed Charge Coverage Ratio of EBITDA to fixed charges as of the end of any fiscal quarter to be less than 2.50 to 1. At December 31, 2020, the actual ratio was 4.34 to 1. • Permit the Consolidated Leverage Ratio of funded debt to EBITDA at any time during any period of four consecutive quarters to be greater than 2.75 to 1. At December 31, 2020, the actual ratio was 0.92 to 1. At December 31, 2020, the Company was in compliance with each of the aforementioned covenants. There are no anticipated trends that the Company is aware of that would indicate non-compliance with these covenants, though, significant deterioration in the Company’s financial performance could impact its ability to comply with these covenants.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 7. INCOME TAXES Income before provision (benefit) for income taxes consisted of the following: (in thousands) Year Ended December 31, 2020 2019 2018 U.S. $ 131,898 $ 129,045 $ 104,881 Foreign 146 80 (186 ) $ 132,044 $ 129,125 $ 104,695 The provision (benefit) for income taxes consisted of the following: (in thousands) Year Ended December 31, 2020 2019 2018 Current: U.S. Federal $ 23,975 $ 11,744 $ 7,270 State 6,545 7,353 4,253 Foreign 1,733 1,616 1,731 32,253 20,713 13,254 Deferred: U.S. Federal (755 ) 10,719 10,355 State (1,424 ) 895 1,637 Foreign (14 ) (8 ) 43 (2,193 ) 11,606 12,035 Total $ 30,060 $ 32,319 $ 25,289 The reconciliation of the U.S. federal statutory tax rate to the Company’s effective tax rate is as follows: Year Ended December 31, 2020 2019 2018 U.S. federal statutory rate 21.0 % 21.0 % 21.0 % State taxes, net of federal benefit 4.7 5.0 5.0 State deferred tax apportionment change, net of federal benefit (1.6 ) 0.1 0.7 Valuation allowance 0.0 0.0 (0.5 ) Share-based compensation (1.4 ) (1.6 ) (1.9 ) Enactment of the Tax Cuts and Jobs Act (0.3 ) (0.1 ) (0.1 ) Other 0.4 0.6 0.0 22.8 % 25.0 % 24.2 % The following table shows the deferred income taxes related to the temporary differences between the tax bases of assets and liabilities and the respective amounts included in “Deferred income taxes, net” on the Company’s Consolidated Balance Sheets: (in thousands) December 31, 2020 2019 Deferred tax liabilities: Accelerated depreciation $ 217,125 $ 221,627 Prepaid costs currently deductible 5,039 5,668 Other 5,970 5,011 Total deferred tax liabilities 228,134 232,306 Deferred tax assets: Accrued costs not yet deductible 9,200 8,860 Allowance for doubtful accounts 536 486 Deferred revenues — 2,512 Share-based compensation 2,321 2,178 Total deferred tax assets, net of valuation allowance of $0.2 million in 2020 and 2019 12,057 14,036 Deferred income taxes, net $ 216,077 $ 218,270 The Tax Cuts and Jobs Act (the “Tax Act”) was enacted in December 2017. Among other provisions, the Tax Act reduced the U.S. federal corporate tax rate from 35% to 21% in 2018, required companies to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred and created new taxes on certain foreign-source earnings. As of December 31, 2019, the Company completed its accounting for the tax effects of enactment of the Tax Act without any material adjustments to its previous estimates. As of December 31, 2020, the Company did not have a deferred tax liability related to its foreign earnings because it did not have any specific plans to repatriate funds from its international subsidiaries. The Company may do so in the future if a dividend can be remitted with no material tax impact. In December 2016, the Company decided to exit the Bangalore, India branch operations of its TRS-RenTelco electronics division. The wind down of operations in India began in 2017. As a result, a valuation allowance was recorded against the deferred tax assets that resulted primarily from accumulated net operating loss carry forwards in India that management estimated the benefit of which will not be realized. As of December 31, 2020, the Company’s foreign net operating losses for tax purposes were $0.6 million. If not realized, these carry forwards will begin to expire in 2023. For income tax purposes, deductible compensation related to share-based awards is based on the value of the award when realized, which may be different than the compensation expense recognized by the company for financial statement purposes which is based on the award value on the date of grant. The difference between the value of the award upon grant, and the value of the award when ultimately realized, creates either additional tax expense or benefit. In 2020, 2019 and 2018 exercise of share-based awards by employees resulted in an excess tax benefit of $1.9 million, $2.1 million and $2.0 million, respectively. The Company recognizes the financial statement benefit of a tax position only after determining that the relevant tax authority would more likely than not sustain the position following an audit. For tax positions meeting the more-likely-than-not threshold, the amount recognized in the financial statements is the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority. The Company evaluated all of its tax positions for which the statute of limitations remained open and determined there were no material unrecognized tax benefits as of December 31, 2020 and 2019. In addition, there have been no material changes in unrecognized benefits during 2020, 2019 and 2018. The Company is subject to income taxes in the U.S. federal jurisdiction, and various states and foreign jurisdictions. Tax regulations within each jurisdiction are subject to interpretation of the related tax laws and regulations and require the application of significant judgment. With few exceptions, the Company is no longer subject to U.S. federal, state and local, or non-U.S. income tax examinations by tax authorities for the years before 2016. Our income tax returns are subject to examination by federal, state and foreign tax authorities. There may be differing interpretations of tax laws and regulations, and as a result, disputes may arise with these tax authorities involving the timing and amount of deductions and allocation of income. The Company recognizes interest and penalties related to unrecognized tax benefits in the provision (benefit) for income taxes in the accompanying Consolidated Statements of Income for all periods presented. Such interest and penalties were not significant for the years ended December 31, 20 20 , 201 9 and 201 8 .

Benefit Plans

Benefit Plans	12 Months Ended
	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Benefit Plans	NOTE 8. BENEFIT PLANS Stock Plans The Company adopted the 2016 Stock Incentive Plan (the “2016 Plan”), effective June 8, 2016, under which 2,000,000 shares of the common stock of the Company, plus the number of shares that remain available for grants of awards under the Company's 2007 Stock Option Plan (the “2007 Plan”) and become available as a result of forfeiture, termination, or expiration of awards previously granted under the 2007 Plan, were reserved for the grant of equity awards to its employees, directors and consultants. The equity awards have a maximum term of 7 years at an exercise price of not less than 100% of the fair market value of the Company's common stock on the date the equity award is granted. The 2016 Plan replaced the 2007 Plan. The 2016 Plan provides for the grant of awards in the form of stock options, stock appreciation rights, restricted stock units (“RSUs”), the vesting of which may be performance-based or service-based, and other rights and benefits. Each RSU issued reduces the number of shares of the Company’s common stock available for grant under the 2016 Plan by two shares. There were no modifications to the 2016 Plan and no awards classified as liabilities in the year ended December 31, 2020. For the years ended December 31, 2020, 2019 and 2018, the share-based compensation expense was $5.5 million, $5.9 million and $4.1 million, respectively, before provision for income taxes. The Company recorded a tax benefit of approximately $1.5 million, $1.6 million and $1.1 million, respectively, related to the aforementioned share-based compensation expenses. There was no capitalized share-based compensation expense in the years ended December 31, 2020, 2019 and 2018. Stock Options As of December 31, 2020, a cumulative total of 9,118,500 shares subject to options have been granted with exercise prices ranging from $3.47 to $40.37. Of these, options have been exercised for the purchase of 6,378,218 shares, while options for 1,670,972 shares have been terminated, and options for 409,410 shares with exercise prices ranging from $24.60 to $40.37 remained outstanding under the stock plans. These options vest over five years and expire seven years after grant. To date, no options have been issued to any of the Company’s non-employee advisors. As of December 31, 2020, 1,548,908 shares remained available for issuance of awards under the stock plans. A summary of the Company’s option activity and related information for the three years ended December 31, 2020 is as follows: Number of options Weighted- average price Weighted- average remaining contractual term (in years) Aggregate intrinsic value (in millions) Balance at December 31, 2017 1,208,860 $ 28.14 Options granted — — Options exercised (332,810 ) 29.49 Options cancelled/forfeited/expired (30,450 ) 28.27 Balance at December 31, 2018 845,600 28.14 Options granted — — Options exercised (260,860 ) 29.55 Options cancelled/forfeited/expired (4,600 ) 30.59 Balance at December 31, 2019 580,140 29.57 Options granted — — Options exercised (163,670 ) 30.22 Options cancelled/forfeited/expired (7,060 ) 28.95 Balance at December 31, 2020 409,410 $ 29.33 2.52 $ 15.5 Exercisable at December 31, 2020 309,695 $ 28.45 2.40 $ 12.0 Expected to vest after December 31, 2020 97,645 $ 32.05 2.95 $ 3.4 The intrinsic value of stock options at any point in time is calculated as the difference between the exercise price of the underlying awards and the quoted price of the Company’s common stock. The aggregate intrinsic value of options exercised and sold under the Company’s stock option plans was $11.9 million, $9.1 million and $9.0 million for the years ended December 31, 2020, 2019 and 2018, respectively, determined as of the date of option exercise. As of December 31, 2020, there was approximately $0.5 million of total unrecognized compensation cost related to unvested share-based compensation option arrangements granted under the Company’s stock plans, which is expected to be recognized over a weighted-average period of less than one year. The following table indicates the options outstanding and options exercisable by exercise price with the weighted-average remaining contractual life for the options outstanding and the weighted-average exercise price at December 31, 2020: Options Outstanding Options Exercisable Exercise price Number outstanding at December Weighted-average remaining contractual life (Years) Weighted-average grant date value Number exercisable at December 31, 2020 Weighted-average grant date value $20 – 25 206,125 2.17 $ 24.60 181,480 $ 24.60 $25 – 30 2,840 2.15 $ 25.12 2,290 $ 25.13 $30 – 35 190,585 2.88 $ 33.97 119,805 $ 33.79 $35 – 40 6,800 3.00 $ 39.19 5,440 $ 39.19 $40 – 45 3,060 3.67 $ 40.37 680 $ 40.37 $20 – 45 409,410 2.52 $ 29.33 309,695 $ 28.45 The Company utilizes the Black-Scholes option-pricing model to estimate the fair value of share-based compensation at the date of grant, which requires the use of accounting judgment and financial estimates, including estimates of the expected term option holders will retain their vested stock options before exercising them, the estimated volatility of the Company’s stock price over the expected term and the expected number of options that will be forfeited prior to the completion of their vesting requirements. Application of alternative assumptions could produce significantly different estimates of the fair value of share-based compensation amounts recognized in the Consolidated Statements of Income. No options were granted in 2020, 2019 and 2018. Restricted Stock Units The following table summarizes the activity of the Company’s RSUs, which includes service-based and performance-based awards, for the three years ended December 31, 2020: Weighted- Aggregate average intrinsic Number grant date value of shares fair value (in millions) Balance at December 31, 2017 93,664 $ 33.62 RSUs granted 97,260 49.47 RSUs vested (30,214 ) 33.16 RSUs cancelled/forfeited/expired (21,200 ) 33.88 Balance at December 31, 2018 139,510 44.73 RSUs granted 83,440 59.98 RSUs vested (25,862 ) 48.31 RSUs cancelled/forfeited/expired (840 ) 59.84 Balance at December 31, 2019 196,248 50.68 RSUs granted 126,540 50.99 RSUs vested (89,225 ) 43.42 RSUs cancelled/forfeited/expired (7,593 ) 57.93 Balance at December 31, 2020 225,970 $ 57.06 $ 15.2 Performance-based RSUs issued prior to 2018 vest over five years, with 60% of the shares immediately vesting after three years when the performance criteria has been determined to have been met and 20% of the remaining shares vesting annually at the anniversary of the performance determination date, subject to continuous employment of the participant. The 2018, 2019 and 2020 performance- based RSU grants vest after three years with 100 % of the shares vesting immediately when performance criteria has been determined to have been met. There were 184,091 performance-based RSUs expected to vest as of December 31, 20 20 . Service based RSUs issued to the Company’s directors generally vest over twelve to fourteen months . Service based RSUs issued to the Company’s management vest over three years. There were 93,040 service-based RSUs expected to vest as of December 31, 20 20 . No forfeitures are currently expected. The total fair value of RSUs that vested during the years ended December 31, 20 20 , 201 9 and 201 8 based on the weighted average grant date values was $ 3.9 million, $ million and $ 1.0 million, respectively. Share-based compensation expense for RSUs for the year ended December 31, 2020, 2019 and 2018 was $4.6 million, $4.7 million and $2.6, respectively. As of December 31, 2020, the total unrecognized compensation expense related to unvested RSUs was $7.0 million and is expected to be recognized over a weighted-average period of 1.6 years. Employee Stock Ownership and 401(k) Plans The McGrath RentCorp Employee Stock Ownership and 401(k) Plan (the “KSOP”) provides that each participant may annually contribute an elected percentage of his or her salary, not to exceed the statutory limit. Each employee who has at least three months of service with the Company and is 21 years or older, is eligible to participate in the KSOP. The Company, at its discretion, may make matching contributions. Contributions are expensed in the year approved by the Board of Directors. Dividends on the Company’s stock held by the KSOP are treated as ordinary dividends and, in accordance with existing tax laws, are deducted by the Company in the year paid. For the year ended December 31, 2020 dividends deducted by the Company were $0.4 million, which resulted in a tax benefit of approximately $0.1 million in 2020. At December 31, 2020, the KSOP held 240,187 shares, or 1% of the Company’s total common shares outstanding. These shares are included in basic and diluted earnings per share calculations.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Shareholders' Equity	NOTE 9. SHAREHOLDERS’ EQUITY The Company has in the past made purchases of shares of its common stock from time to time in over-the-counter market (NASDAQ) transactions, through privately negotiated, large block transactions and through a share repurchase plan, in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934. In August 2015, the Company’s Board of Directors authorized the Company to repurchase 2,000,000 shares of the Company's outstanding common stock (the “Repurchase Plan”). The amount and time of the specific repurchases are subject to prevailing market conditions, applicable legal requirements and other factors, including management’s discretion. All shares repurchased by the Company are canceled and returned to the status of authorized but unissued shares of common stock. There can be no assurance that any authorized shares will be repurchased and the repurchase program may be modified, extended or terminated by the Board of Directors at any time. There were 282,221 shares of common stock repurchased during the twelve months ended December 31, 2020 for the aggregate purchase price of $13.6 million or an average price of $48.25 per repurchased share. There were no repurchases of common stock during the twelve months ended December 31, 2019. As of December 31, 2020, 1,309,805 shares remain authorized for repurchase under the Repurchase Plan.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE 10. COMMITMENTS AND CONTINGENCIES The Company leases certain facilities under various operating leases. Most of the lease agreements provide the Company with the option of renewing its lease at the end of the lease term, at the fair rental value. In most cases, management expects that in the normal course of business, facility leases will be renewed or replaced by other leases. Minimum payments under these leases, exclusive of property taxes and insurance, are as follows: (in thousands) Year Ended December 31, 2021 $ 2,334 2022 1,718 2023 1,356 2024 1,005 2025 293 Thereafter — $ 6,706 Facility rent expense was $3.7 million in 2020, $3.9 million in 2019 and $3.5 million in 2018. The Company is involved in various lawsuits and routine claims arising out of the normal course of its business. The Company maintains insurance coverage for its operations and employees with appropriate aggregate, per occurrence and deductible limits as the Company reasonably determines necessary or prudent with current operations and historical experience. The major policies include coverage for property, general liability, auto, directors and officers, health, and workers’ compensation insurances. The Company records a provision for a liability when it believes that it is both probable that a liability has been incurred and the amount can be reasonably estimated. Significant judgment is required to determine both probability and the estimated amount. The Company reviews these provisions at least quarterly and adjusts these provisions to reflect the impact of negotiations, settlements, rulings, advice of legal counsel, and updated information. Litigation is inherently unpredictable and is subject to significant uncertainties, some of which are beyond the Company’s control. In the opinion of management, there was not at least a reasonable possibility that the ultimate amount of liability not covered by insurance, if any, under any pending litigation and claims, individually or in the aggregate, will have a material adverse effect on the financial position or operating results of the Company. The Company’s health plans are self-funded high deductible plans with annual stop-loss insurance of $200,000 per claim. Beginning in 2019, the Company’s workers compensation insurance is underwritten by an insurance company with no stop-loss value and $350,000 for prior claim years. Insurance providers are responsible for making claim payments that exceed these amounts on an individual claim basis. In addition, the Company has stop loss insurance that pays for claim payments made during a twelve month coverage period that exceeds certain specified thresholds in the aggregate. The Company records an expense when health and workers compensation claim payments are made and accrues for the portion of claims incurred, but not yet paid at period end. The Company makes these accruals based upon a combination of historical claim payments, loss development experience and actuarial estimates. A high degree of judgment is required in developing the underlying assumptions and the resulting amounts to be accrued. In addition, our assumptions will change as the Company’s loss experience develops. All of these factors have the potential for impacting the amounts previously accrued and the Company may be required to increase or decrease the amounts previously accrued. At December 31, 2020 and 2019, accruals for the Company’s health and workers’ compensation high deductible plans were $2.2 million and $2.8 million, respectively.

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible Assets	NOTE 11. INTANGIBLE ASSETS Intangible assets consist of the following: (dollar amounts in thousands) Estimated useful life in years December 31, 2020 December 31, 2019 Trade name Indefinite $ 5,871 $ 5,871 Customer relationships 11 10,644 10,644 Non-compete agreements 5 157 157 16,672 16,672 Less accumulated amortization (9,554 ) (9,338 ) $ 7,118 $ 7,334 Intangible assets with finite useful lives are amortized over their respective useful lives. Amortization expense in the years ended December 31, 2020, 2019 and 2018 was $0.2 million, $0.9 million and $0.9 million, respectively. Based on the carrying values at December 31, 2020 and assuming no subsequent impairment of the underlying assets, the annual amortization is expected to be $0.2 million in 2021 and $0.2 million in 2022 through 2026.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Related Party Transactions	NOTE 12. RELATED PARTY TRANSACTIONS There were no related party transactions in the years ended December 31, 2020 and 2019, or amounts owed to related parties at such dates.

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Segment Reporting	NOTE 13. SEGMENT REPORTING FASB guidelines establish annual and interim reporting standards for an enterprise’s operating segments and related disclosures about its products, services, geographic areas and major customers. In accordance with these guidelines the Company’s four reportable segments are Mobile Modular, TRS-RenTelco, Adler Tanks and Enviroplex. Management focuses on several key measures to evaluate and assess each segment’s performance including rental revenue growth, gross margin, and income before provision for income taxes. Excluding interest expense, allocations of revenue and expense not directly associated with one of these segments are generally allocated to Mobile Modular, TRS-RenTelco and Adler Tanks, based on their pro-rata share of direct revenues. Interest expense is allocated amongst Mobile Modular, TRS-RenTelco and Adler Tanks based on their pro-rata share of average rental equipment at cost, goodwill, intangible assets, accounts receivable, deferred income and customer security deposits. The Company does not report total assets by business segment. Summarized financial information for the years ended December 31, 2020, 2019 and 2018, for the Company’s reportable segments is shown in the following tables: (dollar amounts in thousands) Mobile Modular TRS- RenTelco Adler Tanks Enviroplex 1 Consolidated Year Ended December 31, 2020 Rental revenues $ 188,719 $ 109,083 $ 53,988 $ — $ 351,790 Rental related services revenues 67,527 3,080 21,786 — 92,393 Sales and other revenues 65,278 28,648 1,708 32,737 128,371 Total revenues 321,524 140,811 77,482 32,737 572,554 Depreciation of rental equipment 22,967 46,472 16,427 — 85,866 Gross profit 155,874 60,864 34,079 12,929 263,746 Selling and administrative expenses 68,470 24,306 24,764 5,453 122,993 Income from operations 87,404 36,558 9,315 7,476 140,753 Interest expense (income) allocation 5,104 2,133 2,107 (557 ) 8,787 Income before provision for income taxes 82,300 34,503 7,208 8,033 132,044 Rental equipment acquisitions 39,078 42,588 2,541 — 84,207 Accounts receivable, net (period end) 81,640 22,735 13,655 5,286 123,316 Rental equipment, at cost (period end) 882,115 333,020 315,706 — 1,530,841 Rental equipment, net book value (period end) 611,590 156,536 169,990 — 938,116 Utilization (period end) 2 76.0 % 67.4 % 39.8 % Average utilization 2 77.2 % 66.2 % 44.6 % Segment Data (Continued) (dollar amounts in thousands) Mobile Modular TRS- RenTelco Adler Tanks Enviroplex 1 Consolidated Year Ended December 31, 2019 Rental revenues $ 182,316 $ 103,704 $ 67,869 $ — $ 353,889 Rental related services revenues 69,395 3,260 28,383 — 101,038 Sales and other revenues 49,299 24,519 1,671 39,814 115,303 Total revenues 301,010 131,483 97,923 39,814 570,230 Depreciation of rental equipment 22,071 41,948 16,372 — 80,391 Gross profit 143,618 60,748 47,014 14,785 266,165 Selling and administrative expenses 65,699 24,645 29,321 5,128 124,793 Income from operations 77,919 36,103 17,693 9,657 141,372 Interest expense (income) allocation 7,946 1,970 3,436 (1,021 ) 12,331 Income before benefit for income taxes 69,973 34,217 14,257 10,678 129,125 Rental equipment acquisitions 75,433 89,759 4,826 — 170,018 Accounts receivable, net (period end) 83,182 23,788 17,281 3,848 128,099 Rental equipment, at cost (period end) 868,807 335,343 316,261 — 1,520,411 Rental equipment, net book value (period end) 610,048 172,413 185,039 — 967,500 Utilization (period end) 2 79.1 % 64.5 % 48.4 % Average utilization 2 79.2 % 66.2 % 54.7 % 2018 Rental revenues $ 159,136 $ 89,937 $ 69,701 $ — $ 318,774 Rental related services revenues 54,696 3,300 24,911 — 82,907 Sales and other revenues 40,742 25,420 1,441 29,046 96,649 Total revenues 254,574 118,657 96,053 29,046 498,330 Depreciation of rental equipment 21,200 36,011 15,928 — 73,139 Gross profit 120,750 54,773 48,055 9,673 233,251 Selling and administrative expenses 58,017 22,823 30,026 4,904 115,770 Income from operations 62,733 31,950 18,029 4,769 117,481 Interest expense (income) allocation 7,132 2,696 3,252 (783 ) 12,297 Income before benefit for income taxes 55,601 28,765 14,777 5,552 104,695 Rental equipment acquisitions 63,374 65,467 5,257 — 134,098 Accounts receivable, net (period end) 72,295 20,732 19,992 7,997 121,016 Rental equipment, at cost (period end) 817,375 285,052 313,573 — 1,416,000 Rental equipment, net book value (period end) 572,032 131,450 197,533 — 901,015 Utilization (period end) 2 79.3 % 62.1 % 56.4 % Average utilization 2 78.2 % 62.7 % 59.9 % 1 2 No single customer accounted for more than 10% of total revenues during 2020, 2019 and 2018. Revenue from foreign country customers accounted for 4%, 5% and 4% of the Company’s revenues for the same periods, respectively.

Quarterly Financial Information

Quarterly Financial Information	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information	NOTE 14. QUARTERLY FINANCIAL INFORMATION (unaudited) Quarterly financial information for each of the two years ended December 31, 2020 is summarized below: (in thousands, except per share amounts) 2020 First Second Third Fourth Year Operations Data Rental revenues $ 89,506 $ 85,629 $ 88,138 $ 88,517 $ 351,790 Total revenues 129,453 137,673 156,448 148,980 572,554 Gross profit 61,656 63,232 68,204 70,654 263,746 Income from operations 29,702 32,692 37,333 41,026 140,753 Income before provision for income taxes 26,614 30,625 35,495 39,310 132,044 Net income 20,159 22,549 28,101 31,175 101,984 Earnings per share: Basic $ 0.83 $ 0.93 $ 1.17 $ 1.29 $ 4.22 Diluted $ 0.81 $ 0.92 $ 1.15 $ 1.27 $ 4.16 Dividends declared per share $ 0.420 $ 0.420 $ 0.420 $ 0.420 $ 1.68 Shares used in per share calculations: Basic 24,292 24,121 24,097 24,119 24,157 Diluted 24,738 24,471 24,443 24,453 24,531 Balance Sheet Data Rental equipment, net $ 975,709 $ 969,681 $ 948,125 $ 938,116 $ 938,116 Total assets 1,314,429 1,312,342 1,295,380 1,275,744 1,275,744 Notes payable 291,544 272,149 249,980 222,754 222,754 Shareholders’ equity 637,604 643,836 661,614 682,604 682,604 2019 First Second Third Fourth Year Operations Data Rental revenues $ 82,696 $ 88,105 $ 90,857 $ 92,231 $ 353,889 Total revenues 122,008 127,439 173,562 147,221 570,230 Gross profit 57,005 59,881 78,282 70,997 266,165 Income from operations 27,310 29,066 46,748 38,248 141,372 Income before provision for income taxes 24,251 25,965 43,455 35,454 129,125 Net income 18,449 19,488 32,468 26,401 96,806 Earnings per share: Basic $ 0.76 $ 0.80 $ 1.34 $ 1.09 $ 3.99 Diluted $ 0.75 $ 0.79 $ 1.32 $ 1.07 $ 3.93 Dividends declared per share $ 0.375 $ 0.375 $ 0.375 $ 0.375 $ 1.50 Shares used in per share calculations: Basic 24,195 24,246 24,268 24,290 24,250 Diluted 24,540 24,579 24,632 24,697 24,623 Balance Sheet Data Rental equipment, net $ 912,878 $ 943,152 $ 958,610 $ 967,500 $ 967,500 Total assets 1,239,633 1,280,249 1,306,223 1,309,875 1,309,875 Notes payable 289,464 301,878 301,469 293,431 293,431 Shareholders’ equity 580,643 592,309 616,715 634,036 634,036

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Organization	Organization McGrath RentCorp and its wholly-owned subsidiaries (the “Company”) is a California corporation organized in 1979. The Company is a diversified business to business rental company with four rental divisions; relocatable modular buildings, portable storage containers, electronic test equipment and liquid and solid containment tanks and boxes. Although the Company’s primary emphasis is on equipment rentals, sales of equipment occur in the normal course of business. The Company is comprised of four reportable business segments: modular building and portable storage segment (“Mobile Modular”), electronic test equipment segment (“TRS-RenTelco”), containment solutions for the storage of hazardous and non-hazardous liquids and solids segment (“Adler Tanks”) and classroom manufacturing division selling modular classrooms in California (“Enviroplex”).
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of McGrath RentCorp and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Revenue Recognition	Revenue Recognition Lease revenues - Rental revenues from operating leases are recognized on a straight-line basis over the term of the lease for all operating segments. Rental billings for periods extending beyond period end are recorded as deferred income and are recognized in the period earned. Rental related services revenues are primarily associated with relocatable modular building and liquid and solid containment tanks and boxes leases. For modular building leases, rental related services revenues for modifications, delivery, installation, dismantle and return delivery are lease related because the payments are considered minimum lease payments that are an integral part of the negotiated lease agreement with the customer. These revenues are recognized on a straight-line basis over the term of the lease. Certain leases are accounted for as sales-type leases. For these leases, sales revenue and the related accounts receivable are recognized upon delivery and installation of the equipment and the unearned interest is recognized over the lease term on a basis which results in a constant rate of return on the unrecovered lease investment. Other revenues include interest income on sales-type leases and rental income on facility leases. Non-lease revenues - Sales revenue is recognized upon delivery and installation of the equipment to customers. Certain leases are accounted for as sales-type leases. For these leases, sales revenue and the related accounts receivable are recognized upon delivery and installation of the equipment and the unearned interest is recognized over the lease term on a basis which results in a constant rate of return on the unrecovered lease investment. Other revenue is recognized when earned and primarily includes interest income on sales-type leases, rental income on facility leases and certain logistics services. Sales taxes charged to customers are reported on a net basis and are excluded from revenues and expenses.
Depreciation of Rental Equipment	Depreciation of Rental Equipment Rental equipment is depreciated on a straight-line basis for financial reporting purposes and on an accelerated basis for income tax purposes. The costs of major refurbishment of relocatable modular buildings, portable storage containers and tanks and boxes are capitalized to the extent the refurbishment significantly adds value to, or extends the life of the equipment. Maintenance and repairs are expensed as incurred. The estimated useful lives and residual values of the Company’s rental equipment used for financial reporting purposes are as follows: Relocatable modular buildings 18 years, 50% residual value Relocatable modular accessories 3 to 18 years, no residual value Blast resistant modules 20 years, no residual value Portable storage containers 25 years, 62.5% residual value Electronic test equipment and accessories 1 to 8 years, no residual value Liquid and solid containment tanks and boxes and accessories 3 to 20 years, no residual value
Costs of Rental Related Services	Costs of Rental Related Services Costs of rental related services are primarily associated with relocatable modular building leases and liquid and solid containment tank and boxes. Modular building leases primarily consist of costs for services to be provided under the negotiated lease agreement for delivery, installation, modifications, skirting, additional site-related work, and dismantle and return delivery. Costs related to these services are recognized on a straight-line basis over the term of the lease. Costs of rental related services associated with liquid and solid containment solutions consists of costs of delivery, removal and cleaning of the tanks and boxes. These costs are recognized in the period the service is performed.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company evaluates the carrying value of rental equipment and identifiable definite lived intangible assets for impairment whenever events or circumstances have occurred that would indicate the carrying amount may not be fully recoverable. A key element in determining the recoverability of long-lived assets is the Company’s outlook as to the future market conditions for its rental equipment. If the carrying amount is not fully recoverable, an impairment loss is recognized to reduce the carrying amount to fair value. The Company determines fair value based upon the condition of the rental equipment and the projected net cash flows from its rental and sale considering current market conditions. Goodwill and identifiable indefinite lived assets are evaluated for potential impairment annually or when circumstances indicate potential impairment may have occurred. Impairment losses, if any, are determined based upon the excess of carrying value over the estimated fair value of the asset. There were no impairments of long-lived assets during the years ended December 31, 2020 and 2019. The Company recorded an impairment of modular rental equipment of $0.1 million for the year ended December 31, 2018.
Other Direct Costs of Rental Operations	Other Direct Costs of Rental Operations Other direct costs of rental operations include direct labor, supplies, repairs, insurance, property taxes, license fees, impairment of rental equipment and certain modular lease costs charged to customers in the negotiated rental rate, which are recognized on a straight-line basis over the term of the lease.
Cost of Sales	Cost of Sales Cost of sales in the Consolidated Statements of Income includes the carrying value of the equipment sold and all direct costs associated with the sale.
Warranty Reserves	Warranty Reserves Sales of new relocatable modular buildings, portable storage containers, electronic test equipment and related accessories and liquid and solid containment tanks and boxes not manufactured by the Company are typically covered by warranties provided by the manufacturer of the products sold. The Company typically provides limited 90-day warranties for certain sales of used rental equipment and one-year
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment are stated at cost, net of accumulated depreciation. Depreciation is recognized on a straight-line basis for financial reporting purposes, and on an accelerated basis for income tax purposes. Depreciation expense for property, plant and equipment is included in “Selling and administrative expenses” and “Rental related services” in the Consolidated Statements of Income. Maintenance and repairs are expensed as incurred. Property, plant and equipment consist of the following: (dollar amounts in thousands) Estimated useful life December 31, in years 2020 2019 Land Indefinite $ 54,429 $ 54,423 Land improvements 20 – 50 59,249 52,325 Buildings 30 32,306 29,848 Furniture, office equipment and software 3 – 10 36,882 36,610 Vehicles and machinery 5 – 25 43,101 41,877 225,967 215,083 Less accumulated depreciation (91,514 ) (84,308 ) 134,453 130,775 Construction in progress 1,757 272 $ 136,210 $ 131,047 Property, plant and equipment depreciation expense was $8.6 million, $8.2 million and $8.0 million for the years ended December 31, 2020, 2019 and 2018, respectively. Construction in progress at December 31, 2020 and 2019 consisted primarily of costs related to acquisition of land, land improvements and information technology upgrades.
Capitalized Software Costs	Capitalized Software Costs The Company capitalizes certain development costs incurred in connection with its internal use software. Costs incurred in the preliminary stages of development are expensed as incurred. Once an application has reached the development stage, direct internal and external costs are capitalized until the software is substantially complete and ready for its intended use. These costs generally include external direct costs of materials and services consumed in the project and internal costs, such as payroll and benefits of those employees directly associated with the development of the software. Maintenance, training and post implementation costs are expensed as incurred. The Company also capitalizes costs related to specific upgrades and enhancements when it is probable the expenditures will result in additional functionality. Capitalized software costs are included in property, plant and equipment. The Company capitalized $0.1 million and $3.0 million in internal use software during the years ended December 31, 2020 and 2019, respectively.
Advertising Costs	Advertising Costs Advertising costs are expensed as incurred. Total advertising expenses were $3.9 million, $3.6 million and $3.2 million for the years ended December 31, 2020, 2019 and 2018.
Income Taxes	Income Taxes Income taxes are accounted for using an asset and liability approach. Deferred tax assets and liabilities are recorded for the effect of temporary differences between the tax basis of assets and liabilities and their reported amounts in the consolidated financial statements. Deferred tax assets and deferred tax liabilities are adjusted to the extent necessary to reflect tax rates expected to be in effect when temporary differences reverse. Adjustments may be required to deferred tax assets and deferred tax liabilities due to changes in tax laws and audit adjustments by tax authorities. A valuation allowance would be established if, based on the weight of available evidence, management believes that it is more likely than not that some portion or all of a recorded deferred tax asset would not be realized in future periods. To the extent adjustments are required in any given period, the adjustments would be included within the “Provision for income taxes” in the Consolidated Statements of Income.
Goodwill and Intangible Assets	Goodwill and Intangible Assets Purchase prices of acquired businesses are allocated to the assets and liabilities acquired based on the estimated fair values on the respective acquisition dates. Based on these values, the excess purchase prices over the fair value of the net assets acquired are allocated to goodwill and other intangible assets. Intangible assets related to customer relationships are amortized over eleven years. At December 31, 2020 and 2019, goodwill and trade name intangible assets which have indefinite lives totaled $34.1 million. The Company assesses potential impairment of its goodwill and intangible assets when there is evidence that events or circumstances have occurred that would indicate the recovery of an asset’s carrying value is unlikely. The Company also assesses potential impairment of its goodwill and intangible assets with indefinite lives on an annual basis regardless of whether there is evidence of impairment. If indicators of impairment were to be present in intangible assets used in operations and future discounted cash flows were not expected to be sufficient to recover the assets’ carrying amount, an impairment loss would be charged to expense in the period identified. The amount of an impairment loss would be recognized as the excess of the asset’s carrying value over its fair value. Factors the Company considers important, which may cause impairment include, among others, significant changes in the manner of use of the acquired asset, negative industry or economic trends, and significant underperformance relative to historical or projected operating results. The impairment review of the Company’s goodwill is performed by first assessing qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. The fair value of the reporting unit is compared to its carrying value to determine if the goodwill is impaired. If the fair value of the reporting unit exceeds the carrying value of the net assets assigned to that unit, then goodwill is not impaired. If the carrying value of the net assets assigned to the reporting unit were to exceed its fair value, then a goodwill impairment loss is recorded for the amount the reporting unit’s carrying value exceeds the estimated fair value. The Company conducted its annual impairment analysis in the fourth quarter of 2020. The impairment analysis did not result in an impairment charge for the fiscal year ended 2020. There were no impairment charges in 2019 or 2018. Determining the fair value of a reporting unit is judgmental and involves the use of significant estimates and assumptions. The Company based its fair value estimates on assumptions that it believes are reasonable but are uncertain and subject to changes in market conditions.
Earnings Per Share	Earnings Per Share Basic earnings per share (“EPS”) is computed as net income divided by the weighted average number of shares of common stock outstanding for the period. Diluted EPS is computed assuming conversion of all potentially dilutive securities including the dilutive effects of stock options, unvested restricted stock awards and other potentially dilutive securities. The table below presents the weighted-average common stock used to calculate basic and diluted earnings per share: (in thousands) Year Ended December 31, 2020 2019 2018 Weighted-average common stock for calculating basic earnings per share 24,157 24,250 24,141 Effect of potentially dilutive securities from equity-based compensation 374 373 399 Weighted-average common stock for calculating diluted earnings per share 24,531 24,623 24,540 In 2020, 2019 and 2018, there were no shares having an anti-dilutive effect requiring exclusion from the computation of diluted earnings per share. The Company has made purchases of shares of its common stock from time to time in over-the-counter market (NASDAQ) transactions, through privately negotiated, large block transactions and through a share repurchase plan, in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934. In August 2015, the Company’s Board of Directors authorized the Company to repurchase up to 2,000,000 shares of the Company's outstanding common stock (the “Repurchase Plan”). The amount and time of the specific repurchases are subject to prevailing market conditions, applicable legal requirements and other factors, including management’s discretion. All shares repurchased by the Company are canceled and returned to the status of authorized but unissued shares of common stock. There can be no assurance that any authorized shares will be repurchased and the Repurchase Plan may be modified, extended or terminated by the Board of Directors at any time. In the twelve months ended December 31, 2020, the company repurchased 282,221 shares of its common stock for an average purchase price of $48.25 per share or an aggregate price of $13.6 million. There were no repurchases of common stock during the twelve months ended December 31, 2019 and 2018. As of December 31, 2020, 1,309,805 shares remain authorized for repurchase.
Accounts Receivable and Concentration of Credit Risk	Accounts Receivable and Concentration of Credit Risk The Company’s accounts receivable consist of amounts due from customers for rentals, sales, financed sales and unbilled amounts for the portion of modular building end-of-lease services earned, which were negotiated as part of the lease agreement. Unbilled receivables related to end-of-lease services, which consists of dismantle and return delivery of buildings, were $38.7 million at December 31, 2020 and $37.2 million at December 31, 2019. The Company sells primarily on 30-day terms, individually performs credit evaluation procedures on its customers on each transaction and will require security deposits from its customers when a significant credit risk is identified. The Company records an allowance for doubtful accounts in amounts equal to the estimated losses expected to be incurred in the collection of the accounts receivable. The estimated losses are based on historical collection experience in conjunction with an evaluation of the current status of the existing accounts. Customer accounts are written off against the allowance for doubtful accounts when an account is determined to be uncollectable. The allowance for doubtful accounts activity was as follows: (in thousands) 2020 2019 Beginning balance, January 1 $ 1,883 $ 1,883 Provision for doubtful accounts 1,343 1,013 Write-offs, net of recoveries (1,126 ) (1,013 ) Ending balance, December 31 $ 2,100 $ 1,883 Financial instruments that potentially subject the Company to concentration of credit risk consist primarily of trade accounts receivable. From time to time, the Company maintains cash balances in excess of the Federal Deposit Insurance Corporation limits.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company believes that the carrying amounts for cash, accounts receivable, accounts payable and notes payable approximate their fair values except for fixed rate debt included in notes payable which has an estimated fair value of $103.1 million and $101.4 million compared to the recorded value of $100.0 million as of December 31, 2020 and 2019, respectively. The estimates of fair value of the Company’s fixed rate debt are based on the borrowing rates currently available to the Company for bank loans with similar terms and average maturities.
Foreign Currency Transactions and Translation	Foreign Currency Transactions and Translation The Company's Canadian subsidiary, TRS-RenTelco Inc., a British Columbia corporation (“TRS-Canada”), functions as a branch sales office for TRS-RenTelco in Canada. The functional currency for TRS-Canada is the U.S. dollar. Foreign currency transaction gains and losses of TRS-Canada are reported in the results of operations in the period in which they occur. The Company’s Indian subsidiary, TRS-RenTelco India Private Limited (“TRS-India”), functioned as a rental and sales office for TRS-RenTelco in India, which commenced its closure during 2017. The functional currency for TRS-India is the Indian Rupee. All assets and liabilities of TRS-India are translated into U.S. dollars at period-end exchange rates and all income statement amounts are translated at the average exchange rate for each month within the year. Currently, the Company does not use derivative instruments to hedge its economic exposure with respect to assets, liabilities and firm commitments as the foreign currency transactions and risks to date have not been significant.
Share-Based Compensation	Share-Based Compensation The Company measures and recognizes the compensation expense for all share-based awards made to employees and directors, including stock options, stock appreciation rights (“SARs”) and restricted stock units (“RSUs”), based upon estimated fair values. The fair value of stock options and SARs is estimated on the date of grant using the Black-Scholes option pricing model and for RSUs based upon the fair market value of the underlying shares of common stock as of the date of grant. The Company recognizes share-based compensation cost ratably on a straight-line basis over the requisite service period, which generally equals the vesting period. For performance-based RSUs, compensation costs are recognized when vesting conditions are met. In addition, the Company estimates the probable number of shares of common stock that will be earned and the corresponding compensation cost until the achievement of the performance goal is known.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions in determining reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during each period presented. Actual results could differ from those estimates. The most significant estimates included in the financial statements are the future cash flows and fair values used to determine the recoverability of the rental equipment and identifiable definite lived intangible assets carrying value, the various assets’ useful lives and residual values, and the allowance for doubtful accounts.
Income Tax Position	The Company recognizes the financial statement benefit of a tax position only after determining that the relevant tax authority would more likely than not sustain the position following an audit.  For tax positions meeting the more-likely-than-not threshold, the amount recognized in the financial statements is the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority.
Segment Reporting	FASB guidelines establish annual and interim reporting standards for an enterprise’s operating segments and related disclosures about its products, services, geographic areas and major customers.  In accordance with these guidelines the Company’s four reportable segments are Mobile Modular, TRS-RenTelco, Adler Tanks and Enviroplex. Management focuses on several key measures to evaluate and assess each segment’s performance including rental revenue growth, gross margin, and income before provision for income taxes.    Excluding interest expense, allocations of revenue and expense not directly associated with one of these segments are generally allocated to Mobile Modular, TRS-RenTelco and Adler Tanks, based on their pro-rata share of direct revenues.  Interest expense is allocated amongst Mobile Modular, TRS-RenTelco and Adler Tanks based on their pro-rata share of average rental equipment at cost, goodwill, intangible assets, accounts receivable, deferred income and customer security deposits.  The Company does not report total assets by business segment.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Estimated Useful Lives and Residual Values of Company's Rental Equipment	The estimated useful lives and residual values of the Company’s rental equipment used for financial reporting purposes are as follows: Relocatable modular buildings 18 years, 50% residual value Relocatable modular accessories 3 to 18 years, no residual value Blast resistant modules 20 years, no residual value Portable storage containers 25 years, 62.5% residual value Electronic test equipment and accessories 1 to 8 years, no residual value Liquid and solid containment tanks and boxes and accessories 3 to 20 years, no residual value
Property, Plant and Equipment	Property, plant and equipment consist of the following: (dollar amounts in thousands) Estimated useful life December 31, in years 2020 2019 Land Indefinite $ 54,429 $ 54,423 Land improvements 20 – 50 59,249 52,325 Buildings 30 32,306 29,848 Furniture, office equipment and software 3 – 10 36,882 36,610 Vehicles and machinery 5 – 25 43,101 41,877 225,967 215,083 Less accumulated depreciation (91,514 ) (84,308 ) 134,453 130,775 Construction in progress 1,757 272 $ 136,210 $ 131,047
Weighted-Average Common Stock Used to Calculate Basic and Diluted Earnings per Share	The table below presents the weighted-average common stock used to calculate basic and diluted earnings per share: (in thousands) Year Ended December 31, 2020 2019 2018 Weighted-average common stock for calculating basic earnings per share 24,157 24,250 24,141 Effect of potentially dilutive securities from equity-based compensation 374 373 399 Weighted-average common stock for calculating diluted earnings per share 24,531 24,623 24,540
Summary of Allowance for Doubtful Accounts Activity	The allowance for doubtful accounts activity was as follows: (in thousands) 2020 2019 Beginning balance, January 1 $ 1,883 $ 1,883 Provision for doubtful accounts 1,343 1,013 Write-offs, net of recoveries (1,126 ) (1,013 ) Ending balance, December 31 $ 2,100 $ 1,883

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Summary of Supplemental Cash flow Information Related to Leases	Supplemental cash flow information related to leases was as follows: (in thousands) Year Ended December 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 3,683 $ 3,568 Right of use assets obtained in exchange for lease obligations: Operating leases $ 1,885 $ 2,728
Summary of Maturities of Operating Lease Liabilities	As of December 31, 2020, maturities of operating lease liabilities were as follows: (in thousands) Year ended December 31, 2021 $ 3,294 2022 2,372 2023 1,756 2024 1,066 2025 293 Thereafter — Total lease payments 8,781 Less imputed interest (494 ) $ 8,287
Summary of Maturities of Operating Lease Payments	As of December 31, 2020, maturities of operating lease payments to be received in 2021 and thereafter were as follows: (in thousands) Year Ended December 31, 2021 $ 83,482 2022 24,208 2023 7,680 2024 2,741 2025 542 Thereafter 10 $ 118,663
Minimum Lease Payments Receivable and Net Investment Included in Accounts Receivable for Leases	The minimum lease payments receivable and the net investment are included in Accounts receivable on the Company’s Consolidated Balance Sheet for such leases, which were as follows: (in thousands) December 31, 2020 Gross minimum lease payments receivable $ 1,953 Less – unearned interest (166 ) Net investment in finance lease receivables $ 1,787
Future Minimum Lease Payments under Non-Cancelable Finance Leases	As of December 31, 2020, the future minimum lease payments under non-cancelable finance leases to be received in 2021 and thereafter were as follows: (in thousands) Year Ended December 31, 2021 $ 1,463 2022 267 2023 49 2024 8 Thereafter — Total minimum future lease payments to be received $ 1,787

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 31, 2020
Disaggregation Of Revenue [Abstract]
Summary of Disaggregates the Company's Revenue by Lease and Non Lease	The following table disaggregates the Company’s revenues by lease (within the scope of Topic 840) and non-lease revenues (within the scope of Topic 606) and the underlying service provided for the three years ended December 31, 2020, 2019 and 2018: (in thousands) Mobile Modular TRS- RenTelco Adler Tanks Enviroplex Consolidated Year Ended December 31, 2020 Leasing $ 235,003 $ 112,210 $ 54,710 $ — $ 401,923 Non-lease: Rental related services 22,576 2,618 21,320 — 46,514 Sales 63,863 24,461 1,386 32,737 122,447 Other 82 1,522 66 — 1,670 Total non-lease 86,521 28,601 22,772 32,737 170,631 Total revenues $ 321,524 $ 140,811 $ 77,482 $ 32,737 $ 572,554 2019 Leasing $ 234,032 $ 108,044 $ 68,917 $ — $ 410,993 Non-lease: Rental related services 18,964 2,599 27,634 — 49,197 Sales 47,045 18,995 1,266 39,814 107,120 Other 969 1,845 106 — 2,920 Total non-lease 66,978 23,439 29,006 39,814 159,237 Total revenues $ 301,010 $ 131,483 $ 97,923 $ 39,814 $ 570,230 2018 Leasing $ 200,214 $ 94,345 $ 70,653 $ — $ 365,212 Non-lease: Rental related services 14,870 2,607 24,276 — 41,753 Sales 39,467 19,895 1,044 29,046 89,452 Other 23 1,810 80 — 1,913 Total non-lease 54,360 24,312 25,400 29,046 133,118 Total revenues $ 254,574 $ 118,657 $ 96,053 $ 29,046 $ 498,330

Notes Payable (Tables)

Notes Payable (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Components of Notes Payable	Notes payable consists of the following: (in thousands) December 31, 2020 2019 Unsecured revolving lines of credit $ 122,771 $ 193,459 3.68% Series B senior notes due in 2021 40,000 40,000 3.84% Series C senior notes due in 2022 60,000 60,000 222,771 293,459 Unamortized debt issuance cost (17 ) (28 ) $ 222,754 $ 293,431
Schedule of Future Minimum Payments under Unsecured Revolving Lines of Credit and 4.03% Senior Notes, 3.68% Senior Notes and 3.84% Senior Notes	As of December 31, 2020, the future minimum payments under the unsecured revolving lines of credit, 3.68% Series B senior notes due in 2021 and 3.84% Series C senior notes due in 2022 are as follows: (in thousands) Year Ended December 31, 2021 $ 40,000 2022 60,000 2023 — 2024 — 2025 122,771 $ 222,771
Schedule of Information Related to Lines of Credit	The following information relates to the lines of credit for each of the following periods: (dollar amounts in thousands) Year Ended December 31, 2020 2019 Maximum amount outstanding $ 199,471 $ 219,635 Average amount outstanding $ 170,075 $ 201,195 Weighted average interest rate, during the period 2.11 % 3.59 % Prime interest rate, end of period 3.25 % 4.75 %

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of Income Before Provision (Benefit) for Income Taxes	Income before provision (benefit) for income taxes consisted of the following: (in thousands) Year Ended December 31, 2020 2019 2018 U.S. $ 131,898 $ 129,045 $ 104,881 Foreign 146 80 (186 ) $ 132,044 $ 129,125 $ 104,695
Provision (Benefit) for Income Taxes	The provision (benefit) for income taxes consisted of the following: (in thousands) Year Ended December 31, 2020 2019 2018 Current: U.S. Federal $ 23,975 $ 11,744 $ 7,270 State 6,545 7,353 4,253 Foreign 1,733 1,616 1,731 32,253 20,713 13,254 Deferred: U.S. Federal (755 ) 10,719 10,355 State (1,424 ) 895 1,637 Foreign (14 ) (8 ) 43 (2,193 ) 11,606 12,035 Total $ 30,060 $ 32,319 $ 25,289
Reconciliation of U.S. Federal Statutory Tax Rate to Company's Effective Tax Rate	The reconciliation of the U.S. federal statutory tax rate to the Company’s effective tax rate is as follows: Year Ended December 31, 2020 2019 2018 U.S. federal statutory rate 21.0 % 21.0 % 21.0 % State taxes, net of federal benefit 4.7 5.0 5.0 State deferred tax apportionment change, net of federal benefit (1.6 ) 0.1 0.7 Valuation allowance 0.0 0.0 (0.5 ) Share-based compensation (1.4 ) (1.6 ) (1.9 ) Enactment of the Tax Cuts and Jobs Act (0.3 ) (0.1 ) (0.1 ) Other 0.4 0.6 0.0 22.8 % 25.0 % 24.2 %
Deferred Income Taxes Related to Temporary Differences between Tax Bases of Assets and Liabilities	The following table shows the deferred income taxes related to the temporary differences between the tax bases of assets and liabilities and the respective amounts included in “Deferred income taxes, net” on the Company’s Consolidated Balance Sheets: (in thousands) December 31, 2020 2019 Deferred tax liabilities: Accelerated depreciation $ 217,125 $ 221,627 Prepaid costs currently deductible 5,039 5,668 Other 5,970 5,011 Total deferred tax liabilities 228,134 232,306 Deferred tax assets: Accrued costs not yet deductible 9,200 8,860 Allowance for doubtful accounts 536 486 Deferred revenues — 2,512 Share-based compensation 2,321 2,178 Total deferred tax assets, net of valuation allowance of $0.2 million in 2020 and 2019 12,057 14,036 Deferred income taxes, net $ 216,077 $ 218,270

Benefit Plans (Tables)

Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Company's Option Activity	A summary of the Company’s option activity and related information for the three years ended December 31, 2020 is as follows: Number of options Weighted- average price Weighted- average remaining contractual term (in years) Aggregate intrinsic value (in millions) Balance at December 31, 2017 1,208,860 $ 28.14 Options granted — — Options exercised (332,810 ) 29.49 Options cancelled/forfeited/expired (30,450 ) 28.27 Balance at December 31, 2018 845,600 28.14 Options granted — — Options exercised (260,860 ) 29.55 Options cancelled/forfeited/expired (4,600 ) 30.59 Balance at December 31, 2019 580,140 29.57 Options granted — — Options exercised (163,670 ) 30.22 Options cancelled/forfeited/expired (7,060 ) 28.95 Balance at December 31, 2020 409,410 $ 29.33 2.52 $ 15.5 Exercisable at December 31, 2020 309,695 $ 28.45 2.40 $ 12.0 Expected to vest after December 31, 2020 97,645 $ 32.05 2.95 $ 3.4
Options Outstanding and Options Exercisable by Exercise Price with Weighted-Average Remaining Contractual Life for Options Outstanding and Weighted-Average Exercise Price	The following table indicates the options outstanding and options exercisable by exercise price with the weighted-average remaining contractual life for the options outstanding and the weighted-average exercise price at December 31, 2020: Options Outstanding Options Exercisable Exercise price Number outstanding at December Weighted-average remaining contractual life (Years) Weighted-average grant date value Number exercisable at December 31, 2020 Weighted-average grant date value $20 – 25 206,125 2.17 $ 24.60 181,480 $ 24.60 $25 – 30 2,840 2.15 $ 25.12 2,290 $ 25.13 $30 – 35 190,585 2.88 $ 33.97 119,805 $ 33.79 $35 – 40 6,800 3.00 $ 39.19 5,440 $ 39.19 $40 – 45 3,060 3.67 $ 40.37 680 $ 40.37 $20 – 45 409,410 2.52 $ 29.33 309,695 $ 28.45
Schedule of Weighted-Average Assumptions Used to Determine Fair Value of Option Granted
Summary of Company's Restricted Stock Units Activity	The following table summarizes the activity of the Company’s RSUs, which includes service-based and performance-based awards, for the three years ended December 31, 2020: Weighted- Aggregate average intrinsic Number grant date value of shares fair value (in millions) Balance at December 31, 2017 93,664 $ 33.62 RSUs granted 97,260 49.47 RSUs vested (30,214 ) 33.16 RSUs cancelled/forfeited/expired (21,200 ) 33.88 Balance at December 31, 2018 139,510 44.73 RSUs granted 83,440 59.98 RSUs vested (25,862 ) 48.31 RSUs cancelled/forfeited/expired (840 ) 59.84 Balance at December 31, 2019 196,248 50.68 RSUs granted 126,540 50.99 RSUs vested (89,225 ) 43.42 RSUs cancelled/forfeited/expired (7,593 ) 57.93 Balance at December 31, 2020 225,970 $ 57.06 $ 15.2

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Minimum Payments under Leases, Exclusive of Property Taxes and Insurance	Minimum payments under these leases, exclusive of property taxes and insurance, are as follows: (in thousands) Year Ended December 31, 2021 $ 2,334 2022 1,718 2023 1,356 2024 1,005 2025 293 Thereafter — $ 6,706

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Intangible Assets	Intangible assets consist of the following: (dollar amounts in thousands) Estimated useful life in years December 31, 2020 December 31, 2019 Trade name Indefinite $ 5,871 $ 5,871 Customer relationships 11 10,644 10,644 Non-compete agreements 5 157 157 16,672 16,672 Less accumulated amortization (9,554 ) (9,338 ) $ 7,118 $ 7,334

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Summarized Financial Information for Company's Reportable Segments	Summarized financial information for the years ended December 31, 2020, 2019 and 2018, for the Company’s reportable segments is shown in the following tables: (dollar amounts in thousands) Mobile Modular TRS- RenTelco Adler Tanks Enviroplex 1 Consolidated Year Ended December 31, 2020 Rental revenues $ 188,719 $ 109,083 $ 53,988 $ — $ 351,790 Rental related services revenues 67,527 3,080 21,786 — 92,393 Sales and other revenues 65,278 28,648 1,708 32,737 128,371 Total revenues 321,524 140,811 77,482 32,737 572,554 Depreciation of rental equipment 22,967 46,472 16,427 — 85,866 Gross profit 155,874 60,864 34,079 12,929 263,746 Selling and administrative expenses 68,470 24,306 24,764 5,453 122,993 Income from operations 87,404 36,558 9,315 7,476 140,753 Interest expense (income) allocation 5,104 2,133 2,107 (557 ) 8,787 Income before provision for income taxes 82,300 34,503 7,208 8,033 132,044 Rental equipment acquisitions 39,078 42,588 2,541 — 84,207 Accounts receivable, net (period end) 81,640 22,735 13,655 5,286 123,316 Rental equipment, at cost (period end) 882,115 333,020 315,706 — 1,530,841 Rental equipment, net book value (period end) 611,590 156,536 169,990 — 938,116 Utilization (period end) 2 76.0 % 67.4 % 39.8 % Average utilization 2 77.2 % 66.2 % 44.6 % Segment Data (Continued) (dollar amounts in thousands) Mobile Modular TRS- RenTelco Adler Tanks Enviroplex 1 Consolidated Year Ended December 31, 2019 Rental revenues $ 182,316 $ 103,704 $ 67,869 $ — $ 353,889 Rental related services revenues 69,395 3,260 28,383 — 101,038 Sales and other revenues 49,299 24,519 1,671 39,814 115,303 Total revenues 301,010 131,483 97,923 39,814 570,230 Depreciation of rental equipment 22,071 41,948 16,372 — 80,391 Gross profit 143,618 60,748 47,014 14,785 266,165 Selling and administrative expenses 65,699 24,645 29,321 5,128 124,793 Income from operations 77,919 36,103 17,693 9,657 141,372 Interest expense (income) allocation 7,946 1,970 3,436 (1,021 ) 12,331 Income before benefit for income taxes 69,973 34,217 14,257 10,678 129,125 Rental equipment acquisitions 75,433 89,759 4,826 — 170,018 Accounts receivable, net (period end) 83,182 23,788 17,281 3,848 128,099 Rental equipment, at cost (period end) 868,807 335,343 316,261 — 1,520,411 Rental equipment, net book value (period end) 610,048 172,413 185,039 — 967,500 Utilization (period end) 2 79.1 % 64.5 % 48.4 % Average utilization 2 79.2 % 66.2 % 54.7 % 2018 Rental revenues $ 159,136 $ 89,937 $ 69,701 $ — $ 318,774 Rental related services revenues 54,696 3,300 24,911 — 82,907 Sales and other revenues 40,742 25,420 1,441 29,046 96,649 Total revenues 254,574 118,657 96,053 29,046 498,330 Depreciation of rental equipment 21,200 36,011 15,928 — 73,139 Gross profit 120,750 54,773 48,055 9,673 233,251 Selling and administrative expenses 58,017 22,823 30,026 4,904 115,770 Income from operations 62,733 31,950 18,029 4,769 117,481 Interest expense (income) allocation 7,132 2,696 3,252 (783 ) 12,297 Income before benefit for income taxes 55,601 28,765 14,777 5,552 104,695 Rental equipment acquisitions 63,374 65,467 5,257 — 134,098 Accounts receivable, net (period end) 72,295 20,732 19,992 7,997 121,016 Rental equipment, at cost (period end) 817,375 285,052 313,573 — 1,416,000 Rental equipment, net book value (period end) 572,032 131,450 197,533 — 901,015 Utilization (period end) 2 79.3 % 62.1 % 56.4 % Average utilization 2 78.2 % 62.7 % 59.9 % 1 2

Quarterly Financial Informati_2

Quarterly Financial Information (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information	Quarterly financial information for each of the two years ended December 31, 2020 is summarized below: (in thousands, except per share amounts) 2020 First Second Third Fourth Year Operations Data Rental revenues $ 89,506 $ 85,629 $ 88,138 $ 88,517 $ 351,790 Total revenues 129,453 137,673 156,448 148,980 572,554 Gross profit 61,656 63,232 68,204 70,654 263,746 Income from operations 29,702 32,692 37,333 41,026 140,753 Income before provision for income taxes 26,614 30,625 35,495 39,310 132,044 Net income 20,159 22,549 28,101 31,175 101,984 Earnings per share: Basic $ 0.83 $ 0.93 $ 1.17 $ 1.29 $ 4.22 Diluted $ 0.81 $ 0.92 $ 1.15 $ 1.27 $ 4.16 Dividends declared per share $ 0.420 $ 0.420 $ 0.420 $ 0.420 $ 1.68 Shares used in per share calculations: Basic 24,292 24,121 24,097 24,119 24,157 Diluted 24,738 24,471 24,443 24,453 24,531 Balance Sheet Data Rental equipment, net $ 975,709 $ 969,681 $ 948,125 $ 938,116 $ 938,116 Total assets 1,314,429 1,312,342 1,295,380 1,275,744 1,275,744 Notes payable 291,544 272,149 249,980 222,754 222,754 Shareholders’ equity 637,604 643,836 661,614 682,604 682,604 2019 First Second Third Fourth Year Operations Data Rental revenues $ 82,696 $ 88,105 $ 90,857 $ 92,231 $ 353,889 Total revenues 122,008 127,439 173,562 147,221 570,230 Gross profit 57,005 59,881 78,282 70,997 266,165 Income from operations 27,310 29,066 46,748 38,248 141,372 Income before provision for income taxes 24,251 25,965 43,455 35,454 129,125 Net income 18,449 19,488 32,468 26,401 96,806 Earnings per share: Basic $ 0.76 $ 0.80 $ 1.34 $ 1.09 $ 3.99 Diluted $ 0.75 $ 0.79 $ 1.32 $ 1.07 $ 3.93 Dividends declared per share $ 0.375 $ 0.375 $ 0.375 $ 0.375 $ 1.50 Shares used in per share calculations: Basic 24,195 24,246 24,268 24,290 24,250 Diluted 24,540 24,579 24,632 24,697 24,623 Balance Sheet Data Rental equipment, net $ 912,878 $ 943,152 $ 958,610 $ 967,500 $ 967,500 Total assets 1,239,633 1,280,249 1,306,223 1,309,875 1,309,875 Notes payable 289,464 301,878 301,469 293,431 293,431 Shareholders’ equity 580,643 592,309 616,715 634,036 634,036

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2020USD ($)DivisionSegment$ / sharesshares	Dec. 31, 2019USD ($)shares	Dec. 31, 2018USD ($)shares	Aug. 31, 2015shares
Summary Of Significant Accounting Policies [Line Items]
Number of divisions | Division	4
Number of reportable segments | Segment	4
Impairments of long-lived assets	$ 0	$ 0	$ 39,000
Period for warranties for rental equipment	90 days
Period for warranties for equipment manufactured	1 year
Property, plant and equipment depreciation expenses	$ 8,600,000	8,200,000	8,000,000
Capitalized in internal use of software	100,000	3,000,000
Total advertising expenses	$ 3,900,000	3,600,000	3,200,000
Estimated useful life in years, Customer relationships	11 years
Goodwill and trade name intangible assets	$ 34,100,000	34,100,000
Impairment charges		0	0
Goodwill and intangible assets impairment charge	$ 0	$ 0	$ 0
Anti-dilutive securities excluded from computation of diluted earnings per share | shares	0	0	0
Common stock shares authorized for repurchase | shares				2,000,000
Common stock repurchased | shares	282,221	0	0
Average price per repurchased share | $ / shares	$ 48.25
Aggregate purchase price	$ 13,600,000
Shares remain authorized for repurchase | shares	1,309,805
Unbilled receivables related to end-of-lease services	$ 38,700,000	$ 37,200,000
Period for credit risk identified	30 days
Estimated fair value notes payable	$ 103,100,000	101,400,000
Recorded fair value of notes payable	$ 100,000,000	$ 100,000,000
Modular Rental Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairments of long-lived assets			$ 100,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Estimated Useful Lives and Residual Values of Company's Rental Equipment (Detail)	12 Months Ended
	Dec. 31, 2020
Relocatable modular buildings [Member]
Property, Plant and Equipment [Line Items]
Property subject to or available for operating lease useful life	18 years
Percentage residual value property subject to or available for operating lease	50.00%
Relocatable modular accessories [Member]
Property, Plant and Equipment [Line Items]
Percentage residual value property subject to or available for operating lease	0.00%
Blast resistant modules [Member]
Property, Plant and Equipment [Line Items]
Property subject to or available for operating lease useful life	20 years
Percentage residual value property subject to or available for operating lease	0.00%
Portable storage containers [Member]
Property, Plant and Equipment [Line Items]
Property subject to or available for operating lease useful life	25 years
Percentage residual value property subject to or available for operating lease	62.50%
Electronic test equipment and accessories [Member]
Property, Plant and Equipment [Line Items]
Percentage residual value property subject to or available for operating lease	0.00%
Liquid and solid containment tanks and boxes and accessories [Member]
Property, Plant and Equipment [Line Items]
Percentage residual value property subject to or available for operating lease	0.00%
Minimum [Member] | Relocatable modular accessories [Member]
Property, Plant and Equipment [Line Items]
Property subject to or available for operating lease useful life	3 years
Minimum [Member] | Electronic test equipment and accessories [Member]
Property, Plant and Equipment [Line Items]
Property subject to or available for operating lease useful life	1 year
Minimum [Member] | Liquid and solid containment tanks and boxes and accessories [Member]
Property, Plant and Equipment [Line Items]
Property subject to or available for operating lease useful life	3 years
Maximum [Member] | Relocatable modular accessories [Member]
Property, Plant and Equipment [Line Items]
Property subject to or available for operating lease useful life	18 years
Maximum [Member] | Electronic test equipment and accessories [Member]
Property, Plant and Equipment [Line Items]
Property subject to or available for operating lease useful life	8 years
Maximum [Member] | Liquid and solid containment tanks and boxes and accessories [Member]
Property, Plant and Equipment [Line Items]
Property subject to or available for operating lease useful life	20 years

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 225,967	$ 215,083
Less accumulated depreciation	(91,514)	(84,308)
Property plant and equipment net excluding capitalized cost	134,453	130,775
Construction in progress	1,757	272
Property, Plant and Equipment, net	$ 136,210	131,047
Estimated useful life	3 – 10
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 54,429	54,423
Estimated useful life	Indefinite
Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 59,249	52,325
Land Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	20 years
Land Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	50 years
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 32,306	29,848
Estimated useful life	30 years
Furniture, Office Equipment and Software [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 36,882	36,610
Vehicles and Machinery [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 43,101	$ 41,877
Vehicles and Machinery [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Vehicles and Machinery [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	25 years

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Weighted-Average Common Stock Used to Calculate Basic and Diluted Earnings Per Share (Detail) - shares shares in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Weighted-average common stock for calculating basic earnings per share	24,119	24,097	24,121	24,292	24,290	24,268	24,246	24,195	24,157	24,250	24,141
Effect of potentially dilutive securities from equity-based compensation									374	373	399
Weighted-average common stock for calculating diluted earnings per share	24,453	24,443	24,471	24,738	24,697	24,632	24,579	24,540	24,531	24,623	24,540

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Summary of Allowance for Doubtful Accounts Activity (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Allowance for doubtful accounts, Beginning Balance	$ 1,883	$ 1,883
Provision for doubtful accounts	1,343	1,013	$ 581
Write-offs, net of recoveries	(1,126)	(1,013)
Allowance for doubtful accounts, Ending Balance	$ 2,100	$ 1,883	$ 1,883

Implemented Accounting Pronou_2

Implemented Accounting Pronouncements - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Bad debt expense	$ 1,343,000	$ 1,013,000	$ 581,000
Allowance for doubtful accounts	2,100,000	1,883,000	$ 1,883,000
Net investment in sales-type leases	1,800,000	$ 2,900,000
Credit loss expense	$ 0
Minimum [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Sales-type leases terms	12 months
Maximum [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Sales-type leases terms	36 months

Leases - Additional Information

Leases - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Line Items]
Lessee, operating lease, description	The Company leases real estate for certain of its branch offices and rental equipment storage yards, vehicles and equipment used in its rental operations. The Company determines if an arrangement is a lease at inception. The Company has leases with lease and non-lease components, which are accounted for separately.
Lessee, operating lease, option to extend	true
Lessee, operating lease, option to extend, description	These leases include one or more options to renew, with renewal terms that may extend the lease term from one to three years.
Operating lease, right of use assets	$ 8,300,000	$ 9,900,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PrepaidExpenseAndOtherAssets	us-gaap:PrepaidExpenseAndOtherAssets
Operating lease liabilities	$ 8,287,000	$ 9,900,000
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent
Operating lease expense	$ 3,800,000
Short term lease expense	$ 100,000
Weighted-average remaining lease term for operating leases	3 years 2 months 12 days
Weighted-average discount rate for operating leases	3.95%
Sub-lease income	$ 0
Finance lease liability	$ 0
Lessor, operating lease, description	The Company’s equipment rentals for each of its operating segments are governed by agreements that detail the lease terms and conditions.  The determination of whether these contracts with customers contain a lease generally does not require significant judgement.  The Company accounts for these rentals as operating leases.
Lessor, operating lease, option to extend	true
Lessor, operating lease, option to extend description	Initial lease terms vary in length based upon customer needs and generally range from one to sixty months.
Lease revenue	$ 401,900,000
Operating lease revenue	399,500,000
Finance lease revenue	2,400,000
Finance lease revenue, sales revenue	2,200,000
Finance lease revenue, interest income	$ 200,000
Minimum [Member]
Leases [Line Items]
Lessee, operating lease, renewal term	1 year
Lessor, operating lease, renewal term	1 month
Lessor, operating lease, rental products, useful lives	3 years
Maximum [Member]
Leases [Line Items]
Lessee, operating lease, renewal term	3 years
Lessor, operating lease, renewal term	60 months
Lessor, operating lease, rental products, useful lives	5 years

Leases - Summary of Supplementa

Leases - Summary of Supplemental Cash flow Information Related to Leases (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 3,683	$ 3,568
Right of use assets obtained in exchange for lease obligations:
Operating leases	$ 1,885	$ 2,728

Leases - Summary of Maturities

Leases - Summary of Maturities of Operating Lease Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Operating Lease Liabilities Payments Due [Abstract]
2021	$ 3,294
2022	2,372
2023	1,756
2024	1,066
2025	293
Total lease payments	8,781
Less imputed interest	(494)
Operating lease liabilities	$ 8,287	$ 9,900

Leases - Summary of Maturitie_2

Leases - Summary of Maturities of Operating Lease Payments (Detail) $ in Thousands	Dec. 31, 2020USD ($)
Lessor Operating Lease Payments Fiscal Year Maturity [Abstract]
2021	$ 83,482
2022	24,208
2023	7,680
2024	2,741
2025	542
Thereafter	10
Operating lease, payments to be received	$ 118,663

Leases - Minimum Lease Payments

Leases - Minimum Lease Payments Receivable and Net Investment Included in Accounts Receivable for Leases (Detail) $ in Thousands	Dec. 31, 2020USD ($)
Minimum lease payments receivable and net investment included in accounts receivable for leases
Gross minimum lease payments receivable	$ 1,953
Less – unearned interest	(166)
Net investment in finance lease receivables	$ 1,787

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments under Non-Cancelable Finance Leases (Detail) $ in Thousands	Dec. 31, 2020USD ($)
Future minimum lease payments under non-cancelable finance leases
2021	$ 1,463
2022	267
2023	49
2024	8
Total minimum future lease payments	$ 1,787

Revenue Recognition - Additiona

Revenue Recognition - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disaggregation Of Revenue [Line Items]
Period for credit risk identified	30 days
Sales revenues totaling	$ 17
Unbilled contract assets	$ 38.7	$ 37.2
Period for warranties for rental equipment	90 days
Period for warranties for equipment manufactured	1 year
Deferred Income [Member]
Disaggregation Of Revenue [Line Items]
Customer contract liability	$ 11.3	17.5
Accounts Receivable [Member]
Disaggregation Of Revenue [Line Items]
Unbilled contract assets	$ 1.4	$ 1

Revenue Recognition - Summary o

Revenue Recognition - Summary of Disaggregates the Company's Revenue by Lease and Non Lease (Detail) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation Of Revenue [Line Items]
Leasing revenues										$ 401,900
Total non-lease revenues										128,371	$ 115,303	$ 96,649
Total revenues		$ 148,980	$ 156,448	$ 137,673	$ 129,453	$ 147,221	$ 173,562	$ 127,439	$ 122,008	572,554	570,230	498,330
Leasing [Member]
Disaggregation Of Revenue [Line Items]
Leasing revenues										401,923	410,993	365,212
Non-lease Rental Related Services [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										46,514	49,197	41,753
Non-lease Sales [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										122,447	107,120	89,452
Non-lease Other [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										1,670	2,920	1,913
Non-lease Revenues [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										170,631	159,237	133,118
Mobile Modular [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										65,278	49,299	40,742
Total revenues										321,524	301,010	254,574
Mobile Modular [Member] | Leasing [Member]
Disaggregation Of Revenue [Line Items]
Leasing revenues										235,003	234,032	200,214
Mobile Modular [Member] | Non-lease Rental Related Services [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										22,576	18,964	14,870
Mobile Modular [Member] | Non-lease Sales [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										63,863	47,045	39,467
Mobile Modular [Member] | Non-lease Other [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										82	969	23
Mobile Modular [Member] | Non-lease Revenues [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										86,521	66,978	54,360
TRS-RenTelco [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										28,648	24,519	25,420
Total revenues										140,811	131,483	118,657
TRS-RenTelco [Member] | Leasing [Member]
Disaggregation Of Revenue [Line Items]
Leasing revenues										112,210	108,044	94,345
TRS-RenTelco [Member] | Non-lease Rental Related Services [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										2,618	2,599	2,607
TRS-RenTelco [Member] | Non-lease Sales [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										24,461	18,995	19,895
TRS-RenTelco [Member] | Non-lease Other [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										1,522	1,845	1,810
TRS-RenTelco [Member] | Non-lease Revenues [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										28,601	23,439	24,312
Adler Tanks [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										1,708	1,671	1,441
Total revenues										77,482	97,923	96,053
Adler Tanks [Member] | Leasing [Member]
Disaggregation Of Revenue [Line Items]
Leasing revenues										54,710	68,917	70,653
Adler Tanks [Member] | Non-lease Rental Related Services [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										21,320	27,634	24,276
Adler Tanks [Member] | Non-lease Sales [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										1,386	1,266	1,044
Adler Tanks [Member] | Non-lease Other [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										66	106	80
Adler Tanks [Member] | Non-lease Revenues [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										22,772	29,006	25,400
Enviroplex [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues	[1]									32,737	39,814	29,046
Total revenues	[1]									32,737	39,814	29,046
Enviroplex [Member] | Non-lease Sales [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										32,737	39,814	29,046
Enviroplex [Member] | Non-lease Revenues [Member]
Disaggregation Of Revenue [Line Items]
Total non-lease revenues										$ 32,737	$ 39,814	$ 29,046
[1]	Gross Enviroplex sales revenues were $34,014, $39,814 and $30,407 in 2020, 2019 and 2018, respectively.  There were $1,277 and $1,361 inter-segment sales to Mobile Modular in 2020 and 2018, which have been eliminated in consolidation.  There were no inter-segment sales in 2019.

Notes Payable - Components of N

Notes Payable - Components of Notes Payable (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
Debt Instrument [Line Items]
Notes payable	$ 222,771				$ 293,459
Unamortized debt issuance cost	(17)				(28)
Notes payable, net	222,754	$ 249,980	$ 272,149	$ 291,544	293,431	$ 301,469	$ 301,878	$ 289,464
Unsecured Revolving Lines of Credit [Member]
Debt Instrument [Line Items]
Notes payable	122,771				193,459
Series B senior notes [Member] | 3.68% Series B senior notes due in 2021 [Member]
Debt Instrument [Line Items]
Notes payable	40,000				40,000
Series C senior notes [Member] | 3.84% Series C senior notes due in 2022 [Member]
Debt Instrument [Line Items]
Notes payable	$ 60,000				$ 60,000

Notes Payable - Components of_2

Notes Payable - Components of Notes Payable (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2020	Nov. 05, 2015	Mar. 17, 2014
Series B senior notes [Member] | 3.68% Series B senior notes due in 2021 [Member]
Debt Instrument [Line Items]
Senior Notes, interest rate	3.68%		3.68%
Senior Notes, year of maturity	2021
Series C senior notes [Member] | 3.84% Series C senior notes due in 2022 [Member]
Debt Instrument [Line Items]
Senior Notes, interest rate	3.84%	3.84%
Senior Notes, year of maturity	2022

Notes Payable - Schedule of Fut

Notes Payable - Schedule of Future Minimum Payments under Unsecured Revolving Lines of Credit and 3.68% Senior Notes and 3.84% Senior Notes (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Notes payable	$ 222,771	$ 293,459
Notes Payable to Banks and Others [Member]
Debt Instrument [Line Items]
2021	40,000
2022	60,000
2025	122,771
Notes payable	$ 222,771

Notes Payable - Additional Info

Notes Payable - Additional Information (Detail) - USD ($)	Oct. 01, 2020	Mar. 31, 2020	Nov. 05, 2015	Mar. 17, 2014	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2016
Debt Instrument [Line Items]
Consolidated Fixed Charge Coverage Ratio					2.50%
Consolidated Fixed Charge Coverage Ratio, actual					4.34%
Consolidated Leverage Ratio					275.00%
Consolidated Leverage Ratio, actual					92.00%
Senior notes principal balance outstanding					$ 222,771,000	$ 293,459,000
Note Purchase Agreement [Member] | Notes Issued March 17, 2014 and Due March 17, 2021 [Member]
Debt Instrument [Line Items]
Proceeds from issuance of senior notes		$ 40,000,000
Senior notes interest rate		3.68%
Debt instrument, maturity date					Mar. 17, 2021
Note Purchase Agreement [Member] | Notes Issued November 5, 2015 and Due November 5, 2022 [Member]
Debt Instrument [Line Items]
Proceeds from issuance of senior notes		$ 60,000,000
Senior notes interest rate		3.84%
Debt instrument, maturity date					Nov. 5, 2022
Shelf Notes [Member]
Debt Instrument [Line Items]
Proceeds from issuance of senior notes		$ 250,000,000
Senior notes description					In addition, pursuant to the Note Purchase Agreement, the Company may authorize the issuance and sale of additional senior notes (the “Shelf Notes”) in the aggregate principal amount of (x) $250 million minus (y) the amount of other notes (such as the Series B Senior Notes and Series C Senior Notes, each defined below) then outstanding, to be dated the date of issuance thereof, to mature, in case of each Shelf Note so issued, no more than 15 years after the date of original issuance thereof, to have an average life, in the case of each Shelf Note so issued, of no more than 15 years after the date of original issuance thereof, to bear interest on the unpaid balance thereof from the date thereof at the rate per annum, and to have such other particular terms, as shall be set forth, in the case of each Shelf Note so issued, in accordance with the Note Purchase Agreement.
Rate Lock Agreement [Member] | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Proceeds from issuance of senior notes	$ 40,000,000
Senior notes interest rate	2.57%
Debt instrument, maturity date					Mar. 17, 2021
Debt instrument, term	7 years
3.68% Series B senior notes due in 2021 [Member] | Series B Senior Notes [Member]
Debt Instrument [Line Items]
Proceeds from issuance of senior notes				$ 40,000,000
Senior notes interest rate				3.68%	3.68%
Debt instrument, maturity date					Mar. 17, 2021
Senior notes description					Series B Senior Notes is payable semi-annually beginning on September 17, 2014 and continuing thereafter on March 17 and September 17 of each year until maturity.
Senior notes interest payment					semi-annually
Senior notes principal balance outstanding					$ 40,000,000	40,000,000
3.84% Series C senior notes due in 2022 [Member] | Series C Senior Notes [Member]
Debt Instrument [Line Items]
Proceeds from issuance of senior notes			$ 60,000,000
Senior notes interest rate			3.84%		3.84%
Debt instrument, maturity date					Nov. 5, 2022
Senior notes description					Interest on the Series C Senior Notes is payable semi-annually beginning on May 5, 2016 and continuing thereafter on November 5 and May 5 of each year until maturity.
Senior notes interest payment					semi-annually
Senior notes principal balance outstanding					$ 60,000,000	$ 60,000,000
Debt instrument, date of first required payment					May 5, 2016
Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum		420,000,000
Revolving credit facility, maturity date					Mar. 31, 2025
Additional senior notes indebtedness		250,000,000
Consolidated Fixed Charge Coverage Ratio					2.50%
Consolidated Fixed Charge Coverage Ratio, actual					4.34%
Consolidated Leverage Ratio					275.00%
Consolidated Leverage Ratio, actual					92.00%
Debt instrument description of variable rate basis					(i) LIBOR plus a defined margin, or (ii) the Agent bank’s prime rate (“base rate”) plus a margin.  The applicable margin for each type of loan is measured based upon the Consolidated Leverage Ratio at the end of the prior fiscal quarter and ranges from 1.00% to 1.75% for LIBOR loans and 0% to 0.75% for base rate loans. In addition, the Company pays an unused commitment fee for the portion of the $420.0 million credit facility that is not used. These fees are based upon the Consolidated Leverage Ratio and range from 0.15% to 0.30%. As of December 31, 2020 and 2019, the applicable margins were 1.25% for LIBOR based loans, 0.25% for base rate loans and 0.20% for unused fees. Amounts borrowed under the Sweep Service Facility are based upon the MUFG Union Bank, N.A. base rate plus an applicable margin and an unused commitment fee for the portion of the $12.0 million facility not used.
Unused commitment fees					$ 420,000,000
Credit Facility [Member] | Unused Fees [Member]
Debt Instrument [Line Items]
Debt instrument interest rate at period end					0.20%	0.20%
Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Leverage ratio					0.15%
Credit Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio					0.30%
Credit Facility [Member] | LIBOR Loans [Member]
Debt Instrument [Line Items]
Debt instrument interest rate at period end					1.25%	1.25%
Credit Facility [Member] | LIBOR Loans [Member] | Minimum [Member]
Debt Instrument [Line Items]
Leverage ratio					1.00%
Credit Facility [Member] | LIBOR Loans [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio					1.75%
Credit Facility [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt instrument interest rate at period end					0.25%	0.25%
Credit Facility [Member] | Base Rate Loans [Member] | Minimum [Member]
Debt Instrument [Line Items]
Leverage ratio					0.00%
Credit Facility [Member] | Base Rate Loans [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio					0.75%
Credit Facility [Member] | MUFG Union Bank, N.A [Member]
Debt Instrument [Line Items]
Credit facility, maximum		12,000,000
Revolving credit facility, maturity date					Mar. 31, 2025
Credit Facility [Member] | Treasury Sweep Note Due March 31, 2025 [Member]
Debt Instrument [Line Items]
Credit facility, indebtedness		12,000,000
Revolving credit facility, maturity date					Mar. 31, 2025
Credit Facility [Member] | Notes Issued March 17, 2014 and Due March 17, 2021 [Member]
Debt Instrument [Line Items]
Revolving credit facility, maturity date					Mar. 17, 2021
Credit facility, aggregate outstanding principal		40,000,000
Credit Facility [Member] | Notes Issued November 5, 2015 and Due November 5, 2022 [Member]
Debt Instrument [Line Items]
Revolving credit facility, maturity date					Nov. 5, 2022
Credit facility, aggregate outstanding principal		60,000,000
Credit Facility [Member] | Sweep Service Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum					$ 432,000,000
Credit facility, aggregate outstanding principal					122,800,000
Unused commitment fees					$ 12,000,000
Credit Facility [Member] | One or More Tranches [Member]
Debt Instrument [Line Items]
Revolving credit facility, available maximum borrowing capacity		670,000,000
Letters of Credit [Member]
Debt Instrument [Line Items]
Credit facility, maximum		25,000,000
Swingline Loans [Member]
Debt Instrument [Line Items]
Credit facility, maximum		10,000,000
Unsecured revolving credit facility before Renewal [Member]
Debt Instrument [Line Items]
Credit facility, maximum		$ 420,000,000
Unsecured revolving credit facility before Renewal [Member] | MUFG Union Bank, N.A [Member]
Debt Instrument [Line Items]
Credit facility, maximum							$ 12,000,000

Notes Payable - Schedule of Inf

Notes Payable - Schedule of Information Related to Lines of Credit (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Maximum amount outstanding	$ 199,471	$ 219,635
Average amount outstanding	$ 170,075	$ 201,195
Weighted average interest rate, during the period	2.11%	3.59%
Prime Rate [Member]
Debt Instrument [Line Items]
Prime interest rate, end of period	3.25%	4.75%

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income Before Provision (Benefit) for Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest [Abstract]
U.S.									$ 131,898	$ 129,045	$ 104,881
Foreign									146	80	(186)
Income before provision for income taxes	$ 39,310	$ 35,495	$ 30,625	$ 26,614	$ 35,454	$ 43,455	$ 25,965	$ 24,251	$ 132,044	$ 129,125	$ 104,695

Income Taxes - Provision (Benef

Income Taxes - Provision (Benefit) for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
U.S. Federal	$ 23,975	$ 11,744	$ 7,270
State	6,545	7,353	4,253
Foreign	1,733	1,616	1,731
Current income tax expense (benefit)	32,253	20,713	13,254
Deferred:
U.S. Federal	(755)	10,719	10,355
State	(1,424)	895	1,637
Foreign	(14)	(8)	43
Deferred income tax expense (benefit)	(2,193)	11,606	12,035
Total	$ 30,060	$ 32,319	$ 25,289

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of U.S. Federal Statutory Tax Rate to Company's Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
U.S. federal statutory rate	21.00%	21.00%	21.00%	35.00%
State taxes, net of federal benefit	4.70%	5.00%	5.00%
State deferred tax apportionment change, net of federal benefit	(1.60%)	0.10%	0.70%
Valuation allowance	0.00%	0.00%	(0.50%)
Share-based compensation	(1.40%)	(1.60%)	(1.90%)
Enactment of the Tax Cuts and Jobs Act	(0.30%)	(0.10%)	(0.10%)
Other	0.40%	0.60%	0.00%
Effective Income Tax Rate	22.80%	25.00%	24.20%

Income Taxes - Deferred Income

Income Taxes - Deferred Income Taxes Related to Temporary Differences between Tax Bases of Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax liabilities:
Accelerated depreciation	$ 217,125	$ 221,627
Prepaid costs currently deductible	5,039	5,668
Other	5,970	5,011
Total deferred tax liabilities	228,134	232,306
Deferred tax assets:
Accrued costs not yet deductible	9,200	8,860
Allowance for doubtful accounts	536	486
Deferred revenues		2,512
Share-based compensation	2,321	2,178
Total deferred tax assets, net of valuation allowance of $0.2 million in 2020 and 2019	12,057	14,036
Deferred income taxes, net	$ 216,077	$ 218,270

Income Taxes - Deferred Incom_2

Income Taxes - Deferred Income Taxes Related to Temporary Differences between Tax Bases of Assets and Liabilities (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Deferred tax assets, valuation allowance	$ 0.2	$ 0.2

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Federal corporate tax rate	21.00%	21.00%	21.00%	35.00%
Deferred tax liability related to foreign earnings		$ 0
Excess tax shortfall (benefit) from exercise of share-based awards	$ (1,900,000)	(2,100,000)	$ (2,000,000)
Likelihood percentage of being realized upon ultimate settlement with the relevant tax authority	50.00%
Unrecognized tax benefits	$ 0	0
Changes in unrecognized benefits	0	$ 0	$ 0
Foreign [Member]
Operating Loss Carryforwards [Line Items]
Net operating losses carryforwards	$ 600,000
Net operating losses carryforwards, expiration year	2023

Benefit Plans - Additional Info

Benefit Plans - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jun. 08, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 5,549,000	$ 5,892,000	$ 4,111,000
Tax benefit related to share-based compensation expense	1,500,000	1,600,000	1,100,000
Capitalized share-based compensation expense	$ 0	$ 0	$ 0
Stock option plans remain outstanding	409,410	580,140	845,600	1,208,860
Number of options, granted	0	0	0
Eligible period of service for participation in plan	3 months
Minimum age for employees to participate in KSOP	21 years
Dividends deducted	$ 400,000
Tax benefit from dividends	$ 100,000
Shares outstanding, employee stock ownership plan	240,187
Percentage of total common shares outstanding	1.00%
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional shares authorized	1,548,908
Stock options granted	9,118,500
Stock options, exercise prices lower	$ 3.47
Stock options, exercise prices upper	$ 40.37
Purchase of shares	6,378,218
Stock option shares terminated	1,670,972
Stock option plans remain outstanding	409,410
Stock options outstanding, exercise prices lower	$ 24.60
Stock options outstanding, exercise prices upper	$ 40.37
Stock options vesting period	5 years
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	7 years
Options issued to non-employee advisors	0
Aggregate intrinsic value of options exercised and sold	$ 11,900,000	$ 9,100,000	$ 9,000,000
Total unrecognized compensation cost	$ 500,000
Performance-based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options vesting period	3 years	5 years	5 years
Percentage of vesting annually at anniversary			20.00%
Number of RSU's expected to vest	184,091
Performance-based RSUs [Member] | Vesting after three years [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of vesting RSUs	100.00%	100.00%	60.00%
Service-based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of RSU's expected to vest	93,040
Number of forfeitures expected	0
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected recognition period of unrecognized compensation expense	1 year 7 months 6 days
Number of forfeitures expected	7,593	840	21,200
Total fair value of RSU's vested based on weighted average grant date values	$ 3,900,000	$ 1,200,000	$ 1,000,000
Stock-based compensation expense for restricted stock	4,600,000	$ 4,700,000	$ 2,600,000
Total unrecognized compensation expense net of forfeitures	$ 7,000,000
Maximum [Member] | Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected recognition period of unrecognized compensation expense	1 year
Maximum [Member] | Service-based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options vesting period	14 months
Minimum [Member] | Service-based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options vesting period	12 months
2016 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reduction in common stock available for grant	2
Common Stock [Member] | 2016 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock remained available for grants of awards					2,000,000
Common Stock [Member] | 2016 Stock Incentive Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of award (in years)	7 years
Common Stock [Member] | 2016 Stock Incentive Plan [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Rate of exercise price for equity award granted	100.00%

Benefit Plans - Summary of Comp

Benefit Plans - Summary of Company's Option Activity (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Options, Beginning Balance	580,140	845,600	1,208,860
Number of Options, granted	0	0	0
Number of Options, exercised	(163,670)	(260,860)	(332,810)
Number of Options, cancelled/forfeited/expired	(7,060)	(4,600)	(30,450)
Number of Options, Ending Balance	409,410	580,140	845,600
Number of Options, Exercisable at December 31, 2020	309,695
Number of Options, Expected to Vest after December 31, 2020	97,645
Weighted-Average Price, Beginning Balance	$ 29.57	$ 28.14	$ 28.14
Weighted-Average Price, Options exercised	30.22	29.55	29.49
Weighted-Average Price, Options cancelled/forfeited/expired	28.95	30.59	28.27
Weighted-Average Price, Ending Balance	29.33	$ 29.57	$ 28.14
Weighted-Average Price, Exercisable at December 31, 2020	28.45
Weighted-Average Price, Expected to Vest after December 31, 2020	$ 32.05
Weighted-Average Remaining Contractual Term, Balance At December 31, 2020	2 years 6 months 7 days
Weighted-Average Remaining Contractual Term, Exercisable at December 31, 2020	2 years 4 months 24 days
Weighted-Average Remaining Contractual Term, Expected to Vest after December 31, 2020	2 years 11 months 12 days
Aggregate Intrinsic Value, Balance At December 31, 2020	$ 15.5
Aggregate Intrinsic Value, Exercisable at December 31, 2020	12
Aggregate Intrinsic Value, Expected to Vest after December 31, 2020	$ 3.4

Benefit Plans - Options Outstan

Benefit Plans - Options Outstanding and Options Exercisable by Exercise Price with Weighted-Average Remaining Contractual Life for Options Outstanding and Weighted-Average Exercise Price (Detail)	12 Months Ended
	Dec. 31, 2020$ / sharesshares
Exercise Price 20-25 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Lower Range Limit	$ 20
Exercise Price Upper Range Limit	$ 25
Options Outstanding, Number | shares	206,125
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	2 years 2 months 1 day
Options Outstanding, Weighted-Average Grant Date Value	$ 24.60
Options Exercisable, Number | shares	181,480
Options Exercisable, Weighted-Average Grant Date Value	$ 24.60
Exercise Price 25-30 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Lower Range Limit	25
Exercise Price Upper Range Limit	$ 30
Options Outstanding, Number | shares	2,840
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	2 years 1 month 24 days
Options Outstanding, Weighted-Average Grant Date Value	$ 25.12
Options Exercisable, Number | shares	2,290
Options Exercisable, Weighted-Average Grant Date Value	$ 25.13
Exercise Price 30-35 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Lower Range Limit	30
Exercise Price Upper Range Limit	$ 35
Options Outstanding, Number | shares	190,585
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	2 years 10 months 17 days
Options Outstanding, Weighted-Average Grant Date Value	$ 33.97
Options Exercisable, Number | shares	119,805
Options Exercisable, Weighted-Average Grant Date Value	$ 33.79
Exercise Price 35-40 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Lower Range Limit	35
Exercise Price Upper Range Limit	$ 40
Options Outstanding, Number | shares	6,800
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	3 years
Options Outstanding, Weighted-Average Grant Date Value	$ 39.19
Options Exercisable, Number | shares	5,440
Options Exercisable, Weighted-Average Grant Date Value	$ 39.19
Exercise Price 40-45 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Lower Range Limit	40
Exercise Price Upper Range Limit	$ 45
Options Outstanding, Number | shares	3,060
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	3 years 8 months 1 day
Options Outstanding, Weighted-Average Grant Date Value	$ 40.37
Options Exercisable, Number | shares	680
Options Exercisable, Weighted-Average Grant Date Value	$ 40.37
Exercise Price 20-45 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Lower Range Limit	20
Exercise Price Upper Range Limit	$ 45
Options Outstanding, Number | shares	409,410
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	2 years 6 months 7 days
Options Outstanding, Weighted-Average Grant Date Value	$ 29.33
Options Exercisable, Number | shares	309,695
Options Exercisable, Weighted-Average Grant Date Value	$ 28.45

Benefit Plans - Summary of Co_2

Benefit Plans - Summary of Company's Restricted Stock Units Activity (Detail) - Restricted Stock Units [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Beginning Balance	196,248	139,510	93,664
Number of Shares, granted	126,540	83,440	97,260
Number of Shares, vested	(89,225)	(25,862)	(30,214)
Number of Shares, cancelled/forfeited/expired	(7,593)	(840)	(21,200)
Number of Shares, Ending Balance	225,970	196,248	139,510
Weighted-Average Grant Date Fair Value, Beginning Balance	$ 50.68	$ 44.73	$ 33.62
Weighted-Average Grant Date Fair Value, granted	50.99	59.98	49.47
Weighted-Average Grant Date Fair Value, vested	43.42	48.31	33.16
Weighted-Average Grant Date Fair Value, cancelled/forfeited/expired	57.93	59.84	33.88
Weighted-Average Grant Date Fair Value, Ending Balance	$ 57.06	$ 50.68	$ 44.73
Aggregate Intrinsic Value	$ 15.2

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Aug. 31, 2015
Stockholders Equity Note [Abstract]
Common stock shares authorized for repurchase				2,000,000
Shares remain authorized for repurchase	1,309,805
Common stock repurchased, Shares	282,221	0	0
Aggregate purchase price	$ 13.6
Average price per repurchased share	$ 48.25

Commitments and Contingencies -

Commitments and Contingencies - Minimum Payments under Leases, Exclusive of Property Taxes and Insurance (Detail) $ in Thousands	Dec. 31, 2020USD ($)
Operating Leases Future Minimum Payments Due [Abstract]
2021	$ 2,334
2022	1,718
2023	1,356
2024	1,005
2025	293
Thereafter	0
Total minimum future lease payments	$ 6,706

Commitments and Contingencies_2

Commitments and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Facility rent expense	$ 3,700,000	$ 3,900,000	$ 3,500,000
Health plan annual stop-loss insurance per claim	200,000
Workers compensation insurance with no stop-loss for prior claim years	350,000
Accruals for health and workers' compensation plans	$ 2,200,000	$ 2,800,000

Intangible Assets - Summary of

Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Finite Lived Intangible Assets [Line Items]
Trade name	$ 5,871	$ 5,871
Customer relationships	10,644	10,644
Non-compete agreements	157	157
Intangible Assets, gross	16,672	16,672
Less accumulated amortization	(9,554)	(9,338)
Intangible Assets, net	$ 7,118	$ 7,334
Estimated useful life in years	11 years
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Estimated useful life in years	11 years
Non-compete Agreements [Member]
Finite Lived Intangible Assets [Line Items]
Estimated useful life in years	5 years

Intangible Assets - Additional

Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization expense	$ 200,000	$ 900,000	$ 900,000
Subsequent impairment of the underlying assets	0
Expected annual amortization expense for 2021	200,000
Expected annual amortization expense for 2022	200,000
Expected annual amortization expense for 2023	200,000
Expected annual amortization expense for 2024	200,000
Expected annual amortization expense for 2025	200,000
Expected annual amortization expense for 2026	$ 200,000

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Related Party Transactions [Abstract]
Amount due from (to) related party	$ 0	$ 0

Segment Reporting - Additional

Segment Reporting - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2020SegmentCustomer	Dec. 31, 2019Customer	Dec. 31, 2018Customer
Segment Reporting Information [Line Items]
Number of reportable segments | Segment	4
Customer Concentration Risk [Member] | Sales [Member]
Segment Reporting Information [Line Items]
Number of major customer | Customer	0	0	0
Geographic Concentration Risk [Member] | Sales [Member] | Foreign Country Customers [Member]
Segment Reporting Information [Line Items]
Revenues from customers	4.00%	5.00%	4.00%

Segment Reporting - Summarized

Segment Reporting - Summarized Financial Information for Company's Reportable Segments (Detail) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Rental revenues		$ 88,517	$ 88,138	$ 85,629	$ 89,506	$ 92,231	$ 90,857	$ 88,105	$ 82,696	$ 351,790	$ 353,889	$ 318,774
Rental related services revenues										92,393	101,038	82,907
Sales and other revenues										128,371	115,303	96,649
Total revenues		148,980	156,448	137,673	129,453	147,221	173,562	127,439	122,008	572,554	570,230	498,330
Depreciation of rental equipment										85,866	80,391	73,139
Gross profit		70,654	68,204	63,232	61,656	70,997	78,282	59,881	57,005	263,746	266,165	233,251
Selling and administrative expenses										122,993	124,793	115,770
Income from operations		41,026	37,333	32,692	29,702	38,248	46,748	29,066	27,310	140,753	141,372	117,481
Interest expense (income) allocation										8,787	12,331	12,297
Income before provision/benefit for income taxes		39,310	35,495	30,625	26,614	35,454	43,455	25,965	24,251	132,044	129,125	104,695
Rental equipment acquisitions										84,207	170,018	134,098
Accounts receivable, net (period end)		123,316				128,099				123,316	128,099	121,016
Rental equipment, at cost (period end)		1,530,841				1,520,411				1,530,841	1,520,411	1,416,000
Rental equipment, net book value (period end)		938,116	$ 948,125	$ 969,681	$ 975,709	967,500	$ 958,610	$ 943,152	$ 912,878	938,116	967,500	901,015
Mobile Modular [Member]
Segment Reporting Information [Line Items]
Rental revenues										188,719	182,316	159,136
Rental related services revenues										67,527	69,395	54,696
Sales and other revenues										65,278	49,299	40,742
Total revenues										321,524	301,010	254,574
Depreciation of rental equipment										22,967	22,071	21,200
Gross profit										155,874	143,618	120,750
Selling and administrative expenses										68,470	65,699	58,017
Income from operations										87,404	77,919	62,733
Interest expense (income) allocation										5,104	7,946	7,132
Income before provision/benefit for income taxes										82,300	69,973	55,601
Rental equipment acquisitions										39,078	75,433	63,374
Accounts receivable, net (period end)		81,640				83,182				81,640	83,182	72,295
Rental equipment, at cost (period end)		882,115				868,807				882,115	868,807	817,375
Rental equipment, net book value (period end)		611,590				610,048				$ 611,590	$ 610,048	$ 572,032
Utilization (period end)	[1]									76.00%	79.10%	79.30%
Average utilization	[1]									77.20%	79.20%	78.20%
TRS-RenTelco [Member]
Segment Reporting Information [Line Items]
Rental revenues										$ 109,083	$ 103,704	$ 89,937
Rental related services revenues										3,080	3,260	3,300
Sales and other revenues										28,648	24,519	25,420
Total revenues										140,811	131,483	118,657
Depreciation of rental equipment										46,472	41,948	36,011
Gross profit										60,864	60,748	54,773
Selling and administrative expenses										24,306	24,645	22,823
Income from operations										36,558	36,103	31,950
Interest expense (income) allocation										2,133	1,970	2,696
Income before provision/benefit for income taxes										34,503	34,217	28,765
Rental equipment acquisitions										42,588	89,759	65,467
Accounts receivable, net (period end)		22,735				23,788				22,735	23,788	20,732
Rental equipment, at cost (period end)		333,020				335,343				333,020	335,343	285,052
Rental equipment, net book value (period end)		156,536				172,413				$ 156,536	$ 172,413	$ 131,450
Utilization (period end)	[1]									67.40%	64.50%	62.10%
Average utilization	[1]									66.20%	66.20%	62.70%
Adler Tanks [Member]
Segment Reporting Information [Line Items]
Rental revenues										$ 53,988	$ 67,869	$ 69,701
Rental related services revenues										21,786	28,383	24,911
Sales and other revenues										1,708	1,671	1,441
Total revenues										77,482	97,923	96,053
Depreciation of rental equipment										16,427	16,372	15,928
Gross profit										34,079	47,014	48,055
Selling and administrative expenses										24,764	29,321	30,026
Income from operations										9,315	17,693	18,029
Interest expense (income) allocation										2,107	3,436	3,252
Income before provision/benefit for income taxes										7,208	14,257	14,777
Rental equipment acquisitions										2,541	4,826	5,257
Accounts receivable, net (period end)		13,655				17,281				13,655	17,281	19,992
Rental equipment, at cost (period end)		315,706				316,261				315,706	316,261	313,573
Rental equipment, net book value (period end)		169,990				185,039				$ 169,990	$ 185,039	$ 197,533
Utilization (period end)	[1]									39.80%	48.40%	56.40%
Average utilization	[1]									44.60%	54.70%	59.90%
Enviroplex [Member]
Segment Reporting Information [Line Items]
Sales and other revenues	[2]									$ 32,737	$ 39,814	$ 29,046
Total revenues	[2]									32,737	39,814	29,046
Gross profit	[2]									12,929	14,785	9,673
Selling and administrative expenses	[2]									5,453	5,128	4,904
Income from operations	[2]									7,476	9,657	4,769
Interest expense (income) allocation	[2]									(557)	(1,021)	(783)
Income before provision/benefit for income taxes	[2]									8,033	10,678	5,552
Accounts receivable, net (period end)	[2]	$ 5,286				$ 3,848				$ 5,286	$ 3,848	$ 7,997
[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 $34,014, $39,814 and $30,407 in 2020, 2019 and 2018, respectively.  There were $1,277 and $1,361 inter-segment sales to Mobile Modular in 2020 and 2018, which have been eliminated in consolidation.  There were no inter-segment sales in 2019.

Segment Reporting - Summarize_2

Segment Reporting - Summarized Financial Information for Company's Reportable Segments (Parenthetical) (Detail) - USD ($)		3 Months Ended								12 Months Ended
		Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Revenues		$ 148,980,000	$ 156,448,000	$ 137,673,000	$ 129,453,000	$ 147,221,000	$ 173,562,000	$ 127,439,000	$ 122,008,000	$ 572,554,000	$ 570,230,000	$ 498,330,000
Sales revenues										(128,371,000)	(115,303,000)	(96,649,000)
Sales [Member]
Segment Reporting Information [Line Items]
Sales revenues										(124,604,000)	(110,229,000)	(92,618,000)
Enviroplex [Member]
Segment Reporting Information [Line Items]
Revenues	[1]									32,737,000	39,814,000	29,046,000
Sales revenues	[1]									(32,737,000)	(39,814,000)	(29,046,000)
Mobile Modular [Member]
Segment Reporting Information [Line Items]
Revenues										321,524,000	301,010,000	254,574,000
Sales revenues										(65,278,000)	(49,299,000)	(40,742,000)
Operating Segments [Member] | Enviroplex [Member] | Sales [Member]
Segment Reporting Information [Line Items]
Revenues										34,014,000	39,814,000	30,407,000
Inter-segment Eliminations [Member]
Segment Reporting Information [Line Items]
Sales revenues											$ 0
Type of Revenue [Extensible List]											us-gaap:ProductMember
Inter-segment Eliminations [Member] | Mobile Modular [Member]
Segment Reporting Information [Line Items]
Sales revenues										$ 1,277,000		$ 1,361,000
Type of Revenue [Extensible List]										us-gaap:ProductMember		us-gaap:ProductMember
[1]	Gross Enviroplex sales revenues were $34,014, $39,814 and $30,407 in 2020, 2019 and 2018, respectively.  There were $1,277 and $1,361 inter-segment sales to Mobile Modular in 2020 and 2018, which have been eliminated in consolidation.  There were no inter-segment sales in 2019.

Quarterly Financial Informati_3

Quarterly Financial Information - Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operations Data
Rental revenues	$ 88,517	$ 88,138	$ 85,629	$ 89,506	$ 92,231	$ 90,857	$ 88,105	$ 82,696	$ 351,790	$ 353,889	$ 318,774
Total revenues	148,980	156,448	137,673	129,453	147,221	173,562	127,439	122,008	572,554	570,230	498,330
Gross profit	70,654	68,204	63,232	61,656	70,997	78,282	59,881	57,005	263,746	266,165	233,251
Income from operations	41,026	37,333	32,692	29,702	38,248	46,748	29,066	27,310	140,753	141,372	117,481
Income before provision for income taxes	39,310	35,495	30,625	26,614	35,454	43,455	25,965	24,251	132,044	129,125	104,695
Net income	$ 31,175	$ 28,101	$ 22,549	$ 20,159	$ 26,401	$ 32,468	$ 19,488	$ 18,449	$ 101,984	$ 96,806	$ 79,406
Earnings per share:
Basic	$ 1.29	$ 1.17	$ 0.93	$ 0.83	$ 1.09	$ 1.34	$ 0.80	$ 0.76	$ 4.22	$ 3.99	$ 3.29
Diluted	1.27	1.15	0.92	0.81	1.07	1.32	0.79	0.75	4.16	3.93	3.24
Dividends declared per share	$ 0.420	$ 0.420	$ 0.420	$ 0.420	$ 0.375	$ 0.375	$ 0.375	$ 0.375	$ 1.68	$ 1.50	$ 1.36
Shares used in per share calculations:
Basic	24,119	24,097	24,121	24,292	24,290	24,268	24,246	24,195	24,157	24,250	24,141
Diluted	24,453	24,443	24,471	24,738	24,697	24,632	24,579	24,540	24,531	24,623	24,540
Balance Sheet Data
Rental equipment, net	$ 938,116	$ 948,125	$ 969,681	$ 975,709	$ 967,500	$ 958,610	$ 943,152	$ 912,878	$ 938,116	$ 967,500	$ 901,015
Total assets	1,275,744	1,295,380	1,312,342	1,314,429	1,309,875	1,306,223	1,280,249	1,239,633	1,275,744	1,309,875
Notes payable	222,754	249,980	272,149	291,544	293,431	301,469	301,878	289,464	222,754	293,431
Shareholders’ equity	$ 682,604	$ 661,614	$ 643,836	$ 637,604	$ 634,036	$ 616,715	$ 592,309	$ 580,643	$ 682,604	$ 634,036	$ 571,535	$ 524,184