McGrath RentCorp (MGRC) 10-K 27 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 26, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Trading Symbol	MGRC
Entity Registrant Name	MCGRATH RENTCORP
Entity Central Index Key	752,714
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		24,051,939
Entity Public Float			$ 821,065,768

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets
Cash	$ 2,501	$ 852
Accounts receivable, net of allowance for doubtful accounts of $1,920 in 2017 and $2,087 in 2016	105,872	96,877
Rental equipment, at cost:
Relocatable modular buildings	775,400	769,190
Electronic test equipment	262,325	246,325
Liquid and solid containment tanks and boxes	309,808	308,542
Rental equipment, gross	1,347,533	1,324,057
Less accumulated depreciation	(485,213)	(467,686)
Rental equipment, net	862,320	856,371
Property, plant and equipment, net	119,170	112,190
Prepaid expenses and other assets	22,459	25,583
Intangible assets, net	7,724	8,595
Goodwill	27,808	27,808
Total assets	1,147,854	1,128,276
Liabilities:
Notes payable	303,414	326,266
Accounts payable and accrued liabilities	86,408	78,205
Deferred income	39,219	37,499
Deferred income taxes, net	194,629	292,019
Total liabilities	623,670	733,989
Commitments and contingencies (Note 7)
Shareholders’ equity:
Common Stock, no par value - Authorized 40,000 shares Issued and outstanding - 24,052 shares as of December 31, 2017 and 23,948 shares as of December 31, 2016	102,947	101,821
Retained earnings	421,405	292,521
Accumulated other comprehensive loss	(168)	(55)
Total shareholders’ equity	524,184	394,287
Total liabilities and shareholders’ equity	$ 1,147,854	$ 1,128,276

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 1,920	$ 2,087
Common stock, par value
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	24,052,000	23,948,000
Common Stock, shares outstanding	24,052,000	23,948,000

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues
Rental	$ 289,417	$ 271,388	$ 273,696
Rental related services	78,068	75,859	73,314
Rental operations	367,485	347,247	347,010
Sales	91,500	74,410	55,385
Other	3,049	2,423	2,149
Total revenues	462,034	424,080	404,544
Direct costs of rental operations:
Depreciation of rental equipment	69,908	72,197	75,213
Rental related services	60,029	59,044	57,144
Other	65,472	60,130	58,511
Total direct costs of rental operations	195,409	191,371	190,868
Cost of sales	60,280	48,542	36,769
Total costs of revenues	255,689	239,913	227,637
Gross profit	206,345	184,167	176,907
Selling and administrative expenses	111,605	104,908	99,950
Income from operations	94,740	79,259	76,957
Other income (expense):
Interest expense	(11,622)	(12,207)	(10,092)
Foreign currency exchange gain (loss)	334	(121)	(488)
Income before provision for income taxes	83,452	66,931	66,377
(Benefit) provision for income taxes	(70,468)	28,680	25,907
Net income	$ 153,920	$ 38,251	$ 40,470
Earnings per share:
Basic	$ 6.41	$ 1.60	$ 1.60
Diluted	$ 6.34	$ 1.60	$ 1.59
Shares used in per share calculations:
Basic	23,999	23,900	25,369
Diluted	24,269	23,976	25,457
Cash dividends declared per share	$ 1.04	$ 1.02	$ 1

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 153,920	$ 38,251	$ 40,470
Other comprehensive income (loss):
Foreign currency translation adjustment	(174)	24	55
Tax benefit (provision)	61	(12)	(20)
Comprehensive income	$ 153,807	$ 38,263	$ 40,505

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, 2014	$ 424,531	$ 106,469	$ 318,164	$ (102)
Balance, Shares at Dec. 31, 2014		26,051,000
Net income	40,470		40,470
Share-based compensation	3,399	$ 3,399
Common stock issued under stock plans, net of shares withheld for employee taxes	2,149	$ 2,149
Common stock issued under stock Plans, net of shares withheld for employee taxes, Shares		208,000
Common stock repurchased	(63,953)	$ (9,119)	(54,834)
Common stock repurchased, Shares		(2,408,000)
Tax shortfall from equity awards	(292)	$ (292)
Taxes paid related to net share settlement of stock awards	(1,560)	(1,560)
Dividends accrued of $1.00, $1.02, $1.04 per share in 2015, 2016 and 2017	(25,092)		(25,092)
Other comprehensive (loss) gain	35			35
Balance at Dec. 31, 2015	379,687	$ 101,046	278,708	(67)
Balance, Shares at Dec. 31, 2015		23,851,000
Net income	6,566
Balance at Mar. 31, 2016	380,512
Balance at Dec. 31, 2015	379,687	$ 101,046	278,708	(67)
Balance, Shares at Dec. 31, 2015		23,851,000
Net income	38,251		38,251
Share-based compensation	3,091	$ 3,091
Common stock issued under stock plans, net of shares withheld for employee taxes	$ 37	$ 37
Common stock issued under stock Plans, net of shares withheld for employee taxes, Shares		97,000
Common stock repurchased, Shares	0
Tax shortfall from equity awards	$ (1,066)	$ (1,066)
Taxes paid related to net share settlement of stock awards	(1,287)	(1,287)
Dividends accrued of $1.00, $1.02, $1.04 per share in 2015, 2016 and 2017	(24,438)		(24,438)
Other comprehensive (loss) gain	12			12
Balance at Dec. 31, 2016	$ 394,287	$ 101,821	292,521	(55)
Balance, Shares at Dec. 31, 2016	23,948,000	23,948,000
Balance at Mar. 31, 2016	$ 380,512
Net income	9,079
Balance at Jun. 30, 2016	383,313
Net income	12,872
Balance at Sep. 30, 2016	390,600
Net income	9,734
Balance at Dec. 31, 2016	$ 394,287	$ 101,821	292,521	(55)
Balance, Shares at Dec. 31, 2016	23,948,000	23,948,000
Net income	$ 7,973
Balance at Mar. 31, 2017	396,625
Balance at Dec. 31, 2016	$ 394,287	$ 101,821	292,521	(55)
Balance, Shares at Dec. 31, 2016	23,948,000	23,948,000
Net income	$ 153,920		153,920
Share-based compensation	$ 3,198	$ 3,198
Common stock issued under stock Plans, net of shares withheld for employee taxes, Shares		104,000
Common stock repurchased, Shares	0
Taxes paid related to net share settlement of stock awards	$ (2,072)	$ (2,072)
Dividends accrued of $1.00, $1.02, $1.04 per share in 2015, 2016 and 2017	(25,036)		(25,036)
Other comprehensive (loss) gain	(113)			(113)
Balance at Dec. 31, 2017	$ 524,184	$ 102,947	421,405	(168)
Balance, Shares at Dec. 31, 2017	24,052,000	24,052,000
Balance at Mar. 31, 2017	$ 396,625
Net income	11,461
Balance at Jun. 30, 2017	402,365
Net income	16,762
Balance at Sep. 30, 2017	412,782
Net income	117,724
Balance at Dec. 31, 2017	$ 524,184	$ 102,947	$ 421,405	$ (168)
Balance, Shares at Dec. 31, 2017	24,052,000	24,052,000

Consolidated Statements of Sha7

Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Dividends accrued per share	$ 1.04	$ 1.02	$ 1
Retained Earnings [Member]
Dividends accrued per share	$ 1.04	$ 1.02	$ 1

Consolidated Statements of Cash

Consolidated Statements of Cash Flows	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Cash Flows from Operating Activities:
Net income	$ 153,920,000	$ 38,251,000	$ 40,470,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	78,416,000	81,179,000	84,280,000
Impairment of rental assets	1,639,000	0	0
Provision for doubtful accounts	1,480,000	1,892,000	2,149,000
Share-based compensation	3,198,000	3,091,000	3,399,000
Gain on sale of used rental equipment	(17,733,000)	(13,739,000)	(11,902,000)
Foreign currency exchanges (gain) loss	(334,000)	121,000	488,000
Amortization of debt issuance costs	50,000	51,000	52,000
Change in:
Accounts receivable	(10,475,000)	(3,752,000)	3,628,000
Income taxes receivable		11,000,000	(11,000,000)
Prepaid expenses and other assets	3,124,000	3,219,000	12,910,000
Accounts payable and accrued liabilities	4,015,000	10,426,000	(1,812,000)
Deferred income	1,720,000	1,211,000	7,149,000
Deferred income taxes	(96,631,000)	7,745,000	14,449,000
Net cash provided by operating activities	122,389,000	140,695,000	144,260,000
Cash Flows from Investing Activities:
Purchases of rental equipment	(94,579,000)	(79,038,000)	(131,037,000)
Purchases of property, plant and equipment	(14,617,000)	(10,548,000)	(9,321,000)
Proceeds from sales of used rental equipment	38,344,000	29,406,000	26,214,000
Net cash used in investing activities	(70,852,000)	(60,180,000)	(114,144,000)
Cash Flows from Financing Activities:
Net borrowings (repayments) under bank lines of credit	(2,902,000)	(35,066,000)	18,963,000
Principal payments on Series A senior notes	(20,000,000)	(20,000,000)	(20,000,000)
Borrowings under Series C senior notes			60,000,000
Proceeds from the exercise of stock options		37,000	2,149,000
Taxes paid related to net share settlement of stock awards	(2,072,000)	(1,287,000)	(1,560,000)
Repurchase of common stock			(63,953,000)
Payment of dividends	(24,876,000)	(24,448,000)	(25,779,000)
Net cash used in financing activities	(49,850,000)	(80,764,000)	(30,180,000)
Effect of foreign currency exchange rate changes on cash	(38,000)	(2,000)
Net increase (decrease) in cash	1,649,000	(251,000)	(64,000)
Cash balance, beginning of period	852,000	1,103,000	1,167,000
Cash balance, end of period	2,501,000	852,000	1,103,000
Supplemental Disclosure of Cash Flow Information:
Interest paid, during the period	11,825,000	12,436,000	10,041,000
Net income taxes paid, during the period	29,504,000	15,555,000	2,498,000
Dividends accrued during the period, not yet paid	6,260,000	6,147,000	6,019,000
Rental equipment acquisitions, not yet paid	$ 6,405,000	$ 2,876,000	$ 7,280,000

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
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 Rental revenue from operating leases is recognized on a straight-line basis over the term of the lease. Rental billings for periods extending beyond period end are recorded as deferred income and are recognized when earned. Rental related services revenue is primarily associated with relocatable modular building and liquid and solid containment tanks and boxes leases. For modular building leases, rental related services revenue consists of billings to customers for modifications, delivery, installation, additional site-related work, and dismantle and return delivery. For modular building leases, revenue related to delivery, installation, dismantle and return delivery are an integral part of the negotiated lease agreement with customers and are recognized on a straight-line basis over the term of the lease. For liquid and solid containment solutions, rental related services revenue consists of billings for delivery, removal and cleaning of the tanks and boxes. These revenues are recognized in the period performed. 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 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. The Company recorded an impairment of modular rental equipment of $1.6 million for the year ended December 31, 2017. There were no impairments of long-lived assets during the years ended December 31, 2016 and 2015. 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 warranties on equipment manufactured by Enviroplex. Although the Company’s policy is to provide reserves for warranties when required for specific circumstances, the Company has not found it necessary to establish such reserves to date as warranty costs have not been significant. 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 expenses 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 2017 2016 Land Indefinite $ 50,689 $ 45,928 Land improvements 20 – 50 43,337 42,677 Buildings 30 26,862 26,105 Furniture, office and computer equipment 3 – 10 32,118 35,215 Vehicles and machinery 5 – 25 34,597 30,416 187,603 180,341 Less accumulated depreciation (70,034 ) (68,854 ) 117,569 111,487 Construction in progress 1,601 703 $ 119,170 $ 112,190 Property, plant and equipment depreciation expense was $7.6 million, $8.1 million and $8.2 million for the years ended December 31, 2017, 2016 and 2015, respectively. Construction in progress at December 31, 2017 and 2016 consisted primarily of costs related to acquisition of land and 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 $0.8 million and $0.2 million in internal use software during the years ended December 31, 2017 and 2016, respectively. Advertising Costs Advertising costs are expensed as incurred. Total advertising expenses were $2.9 million, $2.9 million and $2.8 million for the years ended December 31, 2017, 2016 and 2015. 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 have been 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 were allocated to goodwill and other intangible assets. Intangible assets related to customer relationships are amortized over eleven years. At December 31, 2017 and 2016, goodwill and trade name intangible assets which have indefinite lives totaled $33.5 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 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 and indefinite lived assets 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 as a basis for determining whether it is necessary to perform the two-step goodwill impairment test. In the first step, the fair value of the reporting unit is compared to its carrying value to determine if the goodwill and intangible assets are impaired. If the fair value of the reporting unit exceeds the carrying value of the net assets assigned to that unit, then goodwill and intangible assets are not impaired and no further testing is required. If the carrying value of the net assets assigned to the reporting unit were to exceed its fair value, then the second step is performed in order to determine the implied fair value of the reporting unit’s goodwill and intangible assets and an impairment loss is recorded for an amount equal to the difference between the implied fair value and the carrying value of the goodwill and intangible assets. The Company conducted its annual impairment analysis in the fourth quarter of its fiscal year. The impairment analysis did not result in an impairment charge for the fiscal years ended 2017, 2016 or 2015. 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, 2017 2016 2015 Weighted-average common stock for calculating basic earnings per share 23,999 23,900 25,369 Effect of potentially dilutive securities from equity-based compensation 270 76 88 Weighted-average common stock for calculating diluted earnings per share 24,269 23,976 25,457 The following securities were not included in the computation of diluted earnings per share as their effect would have been anti-dilutive: (in thousands) Year Ended December 31, 2017 2016 2015 Options to purchase common stock 7 661 746 In May 2008, the Company’s Board of Directors authorized the Company to repurchase an aggregate of 2,000,000 shares of the Company's outstanding common stock. 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 an additional 2,000,000 shares of the Company's outstanding common stock. 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 no repurchases of common stock during the twelve months ended December 31, 2017 and 2016. As of December 31, 2017, 1,592,026 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 $30.1 million at December 31, 2017 and $28.1 million at December 31, 2016. 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) 2017 2016 Beginning balance, January 1 $ 2,087 $ 2,087 Provision for doubtful accounts 1,480 1,892 Write-offs, net of recoveries (1,647 ) (1,892 ) Ending balance, December 31 $ 1,920 $ 2,087 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 $120.2 million and $140.7 million compared to the recorded value of $120.0 million and $140.0 million as of December 31, 2017 and 2016, 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”), functions 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. The Company records share-based compensation costs in “Selling and administrative expenses” in the Consolidated Statements of Income. The Company recognizes a benefit from share-based compensation in the Consolidated Statements of Shareholders’ Equity if an incremental tax benefit is realized. Further information regarding share-based compensation can be found in “Note 5 –Benefit Plans”. 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. Reclassification In order to conform to our current year presentation, $2.7 million and $2.4 million were reclassified in 2016 and 2015, respectively, from other to rental related services within the direct costs of rental operations on the Condensed Consolidated Statements of Income. These reclassifications had no impact on net income, earnings per share or operating cash flows. New Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers (Topic 606). The objective of this guidance is to establish the principles for reporting useful information to users of financial statements about the nature, timing and uncertainty of revenue from contracts with customers. The new standard is effective for the interim and annual reporting periods beginning after December 31, 2017. The new standard permits two methods of adoption: retrospectively to each prior period presented (full retrospective method), or retrospectively with the cumulative effect of initially applying the guidance recognized at the date of initial application (modified retrospective method). The Company will adopt the guidance effective January 1, 2018 using the modified retrospective method. The Company believes the majority of its revenue, as such revenue relates to rental contractual revenue, is excluded from the scope of this standard, and the remaining revenue streams will not be materially affected. The Company does not anticipate the adoption of this guidance will have a material impact on the Company’s consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases (Subtopic 842-10). Under the new guidance, lessees will be required to recognize the following for all leases (with the exception of short-term leases) on the commencement date: a) lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and During the first quarter 2017, the Company adopted ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting (ASU 2016-09). As a result of the adoption, the Company recognized $869,000 of excess tax benefits related to share-based payments as a reduction to the provision for income taxes for the year ended December 31, 2017. These tax benefits, or shortfalls, were historically recorded in equity. In addition, cash flows related to excess tax benefits, or shortfalls, are now classified as an operating activity with the prior period adjusted accordingly. Cash paid on employees’ behalf related to shares withheld for tax purposes is classified as a financing activity, consistent with prior year’s presentation. Retrospective application of the cash flow presentation requirements resulted in decreases to both net cash provided by operations and net cash used in financing activities of $1,066,000 for the twelve months ended December 31, 2016. The Company’s compensation expense for each period continues to reflect forfeitures as they occur, rather than based upon estimated expected forfeitures. In May 2017, the FASB issued ASU No. 2017-09, Compensation, Stock Compensation (Topic 718). The amendments in this update provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718.

Financed Lease Receivables

Financed Lease Receivables	12 Months Ended
	Dec. 31, 2017
Leases [Abstract]
Financed Lease Receivables	NOTE 2. FINANCED LEASE RECEIVABLES The Company has entered into sales-type leases to finance certain equipment sales to customers. The lease agreements have a bargain purchase option at the end of the lease term. The minimum lease payments receivable and the net investment included in accounts receivable for such leases are as follows: (in thousands) December 31, 2017 2016 Gross minimum lease payments receivable $ 2,150 $ 3,252 Less – unearned interest (201 ) (301 ) Net investment in sales type lease receivables $ 1,949 $ 2,951 As of December 31, 2017, the future minimum lease payments under non-cancelable sales-type leases to be received in 2018 and thereafter are as follows: (in thousands) Year Ended December 31, 2018 $ 1,354 2019 633 2020 163 Total minimum future lease payments $ 2,150

Notes Payable

Notes Payable	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Notes Payable	NOTE 3. NOTES PAYABLE Notes payable consists of the following: (in thousands) December 31, 2017 2016 Unsecured revolving lines of credit $ 183,473 $ 186,376 4.03% Series A senior notes due in 2018 20,000 40,000 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 $ 303,473 $ 326,376 As of December 31, 2017, the future minimum payments under the unsecured revolving lines of credit, 4.03% Series A senior notes due in 2018, 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, 2018 $ 20,000 2019 — 2020 — 2021 223,473 2022 60,000 $ 303,473 Unsecured Revolving Lines of Credit In March 2016, the Company renewed its credit agreement with a syndicate of banks (the “Credit Facility”). The five-year facility matures on March 31, 2021 and replaced the Company’s prior $420.0 million unsecured revolving credit facility. The Credit Facility provides for a $420.0 million unsecured revolving credit facility (which may be increased to $620.0 million with $200.0 million of additional 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. In March 2016, the Company entered into a Credit Facility Letter Agreement and a Credit Line Note in favor of MUFG Union Bank, N.A., extending its line of credit facility related to its cash management services (“Sweep Service Facility”) and increasing the facility size from $10.0 million to $12.0 million. The Sweep Service Facility matures on the earlier of March 31, 2021, or the date the Company ceases to utilize MUFG Union Bank, N.A. for its cash management services. At December 31, 2017, 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 $183.5 million was outstanding, and had capacity to borrow up to an additional $248.5 million. 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, 2017, the actual ratio was 6.82 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, 2017, the actual ratio was 1.70 to 1. • Permit Tangible Net Worth as of the end of any fiscal quarter of the Company to be less than the sum of (i) $246.1 million plus (ii) 25% of the Company’s Consolidated Net Income (as defined in the Amended Credit Facility) (but only if a positive number) for each fiscal quarter ended subsequent to December 31, 2011 plus (iii) 90% of the net cash proceeds from the issuance of the Company’s capital stock after December 31, 2011. At December 31, 2017, such sum was $349.9 million and the actual Tangible Net Worth of the Company was $488.7 million. 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, 2017 and 2016, the applicable margins were 1.25% and 1.50% for LIBOR based loans, respectively, 0.25% and 0.50% for base rate loans, respectively and 0.20% and 0.25% for unused fees, respectively. 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, 2017 2016 Maximum amount outstanding $ 215,732 $ 239,820 Average amount outstanding $ 199,499 $ 214,446 Weighted average interest rate, during the period 2.64 % 2.19 % Prime interest rate, end of period 4.50 % 3.75 % 4.03% Senior Notes Due in 2018 On April 21, 2011, the Company entered into a Note Purchase and Private Shelf Agreement (the “Note Purchase Agreement”) with Prudential Investment Management, Inc. (“PIM”), The Prudential Insurance Company of America and Prudential Retirement Insurance and Annuity Company (collectively, the “Purchaser”), pursuant to which the Company agreed to sell an aggregate principal amount of $100.0 million of its 4.03% Series A Senior Notes (the “Series A Senior Notes”) to the Purchaser. The Series A Senior Notes are an unsecured obligation of the Company, due on April 21, 2018. Interest on these notes is due semi-annually in arrears and the principal is due in five equal annual installments, with the first payment due on April 21, 2014. At December 31, 2017 and 2016, the principal balance outstanding under the Series A Senior Notes were $20.0 million and $40.0 million, respectively. 3.68% Senior Notes Due in 2021 On March 17, 2014, the Company issued and sold to the Purchasers 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 Note Purchase Agreement, as amended. The Series B Senior Notes are an unsecured obligation of the Company, 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, 2017 and 2016, 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 Purchasers 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 Note Purchase Agreement, as amended. The Series C Senior Notes are an unsecured obligation of the Company, 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 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, 2017 and 2016, 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, 2017, the actual ratio was 6.82 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, 2017, the actual ratio was 1.70 to 1. • Permit Tangible Net Worth, calculated as of the last day of each fiscal quarter, to be less than the sum of (i) $229.0 million, plus (ii) 25% of net income for such fiscal quarter subsequent to December 31, 2010, plus (iii) 90% of the net cash proceeds from the issuance of the Company’s capital stock after December 31, 2010. At December 31, 2017, such sum was $349.9 million and the actual Tangible Net Worth of the Company was $488.7 million. At December 31, 2017, 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. On February 9, 2016, the Company entered into an amendment to the Note Purchase Agreement (“2016 Amendment”) with the Purchaser. Pursuant to the 2016 Amendment, (i) the issuance period for the shelf notes to be issued and sold pursuant to the Note Purchase Agreement is extended until the earlier of February 9, 2019 or the termination of the issuance and sale of the shelf notes upon the 30 days’ prior notice of either PIM or the Company, and (ii) the definition of the “Available Facility Amount,” which is the aggregate amount of the shelf notes that may be authorized for purchase pursuant to the Note Purchase Agreement was amended to equal a formula based on: $250 million, minus the aggregate principal amount of the shelf notes then outstanding and purchased pursuant to the Note Purchase Agreement, minus the shelf notes accepted by the Company for purchase, but not yet purchased, by the Purchaser pursuant to the Note Purchase Agreement; provided, however, the aggregate amount of the shelf notes purchased by any corporation or other entity controlling, controlled by, or under common control with, PIM shall not exceed $200 million.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 4. INCOME TAXES Income before (benefit) provision for income taxes consisted of the following: (in thousands) Year Ended December 31, 2017 2016 2015 U.S. $ 83,525 $ 67,199 $ 66,889 Foreign (73 ) (268 ) (512 ) $ 83,452 $ 66,931 $ 66,377 The (benefit) provision for income taxes consisted of the following: (in thousands) Year Ended December 31, 2017 2016 2015 Current: U.S. Federal $ 21,171 $ 17,203 $ 7,976 State 2,976 2,049 1,851 Foreign 2,016 1,683 1,645 26,163 20,935 11,472 Deferred: U.S. Federal (103,518 ) 4,005 13,201 State 6,948 3,039 1,538 Foreign (61 ) 701 (304 ) (96,631 ) 7,745 14,435 Total $ (70,468 ) $ 28,680 $ 25,907 The reconciliation of the U.S. federal statutory tax rate to the Company’s effective tax rate is as follows: Year Ended December 31, 2017 2016 2015 U.S. federal statutory rate 35.0 % 35.0 % 35.0 % State taxes, net of federal benefit 4.1 4.2 4.2 State deferred tax rate change, net of federal benefit 0.5 2.0 (0.4 ) Valuation allowance 0.1 1.1 — Share-based compensation (1.0 ) — — Enactment of the Tax Cuts and Jobs Act (122.9 ) — — Other (0.2 ) 0.6 0.2 (84.4 )% 42.9 % 39.0 % 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, 2017 2016 Deferred tax liabilities: Accelerated depreciation $ 195,694 $ 293,141 Prepaid costs currently deductible 4,152 6,572 Other 4,405 5,747 Total deferred tax liabilities 204,251 305,460 Deferred tax assets: Accrued costs not yet deductible 7,880 9,785 Allowance for doubtful accounts 484 809 Deferred revenues 213 965 Share-based compensation 1,045 1,882 Total deferred tax assets, net of valuation allowance of $0.8 million in 2017 and $0.7 million in 2016 9,622 13,441 Deferred income taxes, net $ 194,629 $ 292,019 The Tax Cuts and Jobs Act (the “Tax Act”) was enacted in December 2017. Among other provisions, the Tax Act reduces the U.S. federal corporate tax rate from 35% to 21% and requires companies to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred. As a result of the Tax Act, the Company re-measured its net deferred tax liabilities and recognized a net tax benefit of $102.8 million. Additionally, based on information currently available to us, we recorded a provisional income tax expense of $0.3 million related to the deemed repatriation of foreign earnings. The Company did not have a deferred tax liability related to its foreign earnings because permanent reinvestment was previously asserted. It is the Company’s intent to continue to permanently reinvest such earnings. The Company will continue to obtain and analyze information related to the deemed repatriation of foreign earnings associated with historical ownership and financial information and will finalize the provision within one year of the enactment date. In addition, there is currently uncertainty as to what portions if any of the Tax Act will be adopted by the U.S. state and local taxing authorities. 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 as of December 31, 2017 that management estimated the benefit of which will not be realized. As of December 31, 2017, the Company’s foreign net operating losses for tax purposes were $0.4 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 2017, exercise of share-based awards by employees resulted in an excess tax benefit of $0.9 million. In 2016 and 2015 the exercise of share-based awards by employees resulted in a tax shortfall of $1.1 million and $0.3 million, respectively, which was recorded to equity. 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, 2017 and 2016. In addition, there have been no material changes in unrecognized benefits during 2017, 2016 and 2015. 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 2013. 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 (benefit) provision 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, 2017, 2016 and 2015.

Benefit Plans

Benefit Plans	12 Months Ended
	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Benefit Plans	NOTE 5. 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, 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, 2017. For the years ended December 31, 2017, 2016 and 2015, the share-based compensation expense was $3.2 million, $3.1 million and $3.4 million, respectively, before provision for income taxes. The Company recorded a tax benefit of approximately $1.3 million, $1.2 million and $1.3 million, respectively, related to the aforementioned share-based compensation expenses. There was no capitalized share-based compensation expense in the years ended December 31, 2017, 2016 and 2015. Stock Options As of December 31, 2017, a cumulative total of 8,458,600 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 5,620,878 shares, while options for 1,628,622 shares have been terminated, and options for 1,208,860 shares with exercise prices ranging from $23.84 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, 2017, 2,097,594 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, 2017 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, 2014 1,343,760 $ 27.25 Options granted 456,200 31.69 Options exercised (270,650 ) 19.81 Options cancelled/forfeited/expired (118,660 ) 29.58 Balance at December 31, 2015 1,410,650 29.91 Options granted 881,800 25.26 Options exercised (368,085 ) 27.34 Options cancelled/forfeited/expired (339,930 ) 28.62 Balance at December 31, 2016 1,584,435 28.14 Options granted 299,600 34.66 Options exercised (398,275 ) 28.94 Options cancelled/forfeited/expired (276,900 ) 28.04 Balance at December 31, 2017 1,208,860 $ 29.52 4.94 $ 21.1 Exercisable at December 31, 2017 325,680 $ 28.65 4.04 $ 6.0 Expected to vest after December 31, 2017 680,049 $ 29.78 5.28 $ 11.7 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 $6.2 million, $4.2 million and $5.7 million for the years ended December 31, 2017, 2016 and 2015, respectively, determined as of the date of option exercise. As of December 31, 2017, there was approximately $4.3 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 2.7 years. 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, 2017: 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, 2017 Weighted- average grant date value $20 – 25 481,510 5.13 $ 24.59 125,505 $ 24.58 $25 – 30 57,505 3.14 $ 28.05 37,300 $ 28.91 $30 – 35 654,265 4.94 $ 33.07 160,635 $ 32.09 $35 – 40 8,780 5.32 $ 38.61 2,240 $ 38.18 $40 – 45 6,800 6.67 $ 40.37 — $ — $20 – 45 1,208,860 4.94 $ 29.52 325,680 $ 28.65 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. The fair value of each option granted was estimated on the date of grant using the Black-Scholes option-pricing model using the following weighted-average assumptions: Year Ended December 31, 2017 2016 2015 Expected term (in years) 5.0 5.0 5.0 Expected volatility 26.1 % 28.7 % 31.1 % Expected dividend yields 3.0 % 4.1 % 3.2 % Risk-free interest rates 2.0 % 1.2 % 1.6 % The Company monitors option exercise behavior to determine the appropriate homogenous groups for estimation purposes. Currently, the Company’s option activity is separated into two categories: directors and employees. The expected term of the options represents the estimated period of time until exercise and is based on historical experience, giving consideration to the option terms, vesting schedules and expectations of future behavior. Expected stock volatility is based on historical stock price volatility of the Company and the risk-free interest rates are based on U.S. Treasury yields in effect on the date of the option grant for the estimated period the options will be outstanding. The expected dividend yield is based upon the current dividend annualized as a percentage of the grant exercise price. The weighted average grant date fair value per share was $6.28, $4.14 and $6.60 during the years ended December 31, 2017, 2016 and 2015, respectively. 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, 2017: Weighted- Aggregate average intrinsic Number grant date value of shares fair value (in millions) Balance at December 31, 2014 311,583 $ 29.78 RSUs granted 79,300 31.86 RSUs vested (89,915 ) 27.97 RSUs cancelled/forfeited/expired (80,320 ) 31.35 Balance at December 31, 2015 220,648 30.70 RSUs granted 31,900 25.75 RSUs vested (59,008 ) 29.69 RSUs cancelled/forfeited/expired (68,300 ) 29.33 Balance at December 31, 2016 125,240 30.66 RSUs granted 70,960 34.53 RSUs vested (36,336 ) 26.99 RSUs cancelled/forfeited/expired (66,200 ) 32.63 Balance at December 31, 2017 93,664 $ 33.62 $ 4.4 Performance-based RSUs 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. There were 112,834 performance-based RSUs expected to vest as of December 31, 2017. Service-based RSUs have been issued to the Company’s directors and generally vest over twelve to fourteen months. There were 17,600 service-based RSUs expected to vest as of December 31, 2017. No forfeitures are currently expected. The total fair value of RSUs that vested during the years ended December 31, 2017, 2016 and 2015 based on the weighted average grant date values was $1.0 million, $1.8 million and $2.5 million, respectively. Share-based compensation expense for RSUs for the year ended December 31, 2017, 2016 and 2015 was $1.4 million, $1.0 million and $1.7, respectively. As of December 31, 2017, the total unrecognized compensation expense related to unvested RSUs was $1.7 million and is expected to be recognized over a weighted-average period of 2.2 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, 2016 dividends deducted by the Company were $0.3 million, which resulted in a tax benefit of approximately $0.1 million in 2017. At December 31, 2017, the KSOP held 258,482 shares, or less than 2% 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, 2017
Equity [Abstract]
Shareholders' Equity	NOTE 6. SHAREHOLDERS’ EQUITY In May 2008, the Company’s Board of Directors authorized the Company to repurchase an aggregate of 2,000,000 shares of the Company's outstanding common stock. 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 an additional 2,000,000 shares of the Company's outstanding common stock. 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 no repurchases of common stock during the twelve months ended December 31, 2017 and 2016. As of December 31, 2017, 1,592,026 shares remain authorized for repurchase under this authorization.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE 7. 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, 2018 $ 1,632 2019 1,282 2020 941 2021 839 2022 863 Thereafter 1,964 $ 7,521 Rent expense was $3.6 million, $3.5 million and $3.5 million in 2017, 2016 and 2015, respectively. 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 and workers’ compensation plans are self-funded high deductible plans with annual stop-loss insurance of $200,000 and $250,000 per claim, respectively. 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, 2017 and 2016, accruals for the Company’s health and workers’ compensation high deductible plans were $2.9 million and $2.4 million, respectively.

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible Assets	NOTE 8. INTANGIBLE ASSETS Intangible assets consist of the following: (dollar amounts in thousands) Estimated useful life December 31, (In years) 2017 2016 Trade name Indefinite $ 5,700 $ 5,700 Customer relationships 11 9,611 9,611 15,311 15,311 Less accumulated amortization (7,587 ) (6,716 ) $ 7,724 $ 8,595 Intangible assets with finite useful lives are amortized over their respective useful lives. Amortization expense in each of the years ended December 31, 2017, 2016 and 2015 were $0.9 million. Based on the carrying values at December 31, 2017 and assuming no subsequent impairment of the underlying assets, the annual amortization is expected to be $0.9 million in 2018 through 2019 and $0.2 million in 2020.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2017
Related Party Transactions [Abstract]
Related Party Transactions	NOTE 9. RELATED PARTY TRANSACTIONS There were no related party transactions in the years ended December 31, 2017 and 2016, or amounts owed to related parties at such dates.

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Segment Reporting	NOTE 10. 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, 2017, 2016 and 2015, for the Company’s reportable segments is shown in the following tables: Segment Data (dollar amounts in thousands) Mobile Modular TRS- RenTelco Adler Tanks Enviroplex 1 Consolidated Year Ended December 31, 2017 Rental revenues $ 142,584 $ 82,812 $ 64,021 $ — $ 289,417 Rental related services revenues 50,448 2,858 24,762 — 78,068 Sales and other revenues 38,234 22,374 2,572 31,369 94,549 Total revenues 231,266 108,044 91,355 31,369 462,034 Depreciation of rental equipment 21,247 32,891 15,770 — 69,908 Gross profit 103,935 50,289 43,218 8,903 206,345 Selling and administrative expenses 55,583 22,171 29,542 4,309 111,605 Income from operations 48,352 28,118 13,676 4,594 94,740 Interest expense (income) allocation (6,671 ) (2,320 ) (3,071 ) 440 (11,622 ) Income before (benefit) provision for income taxes 41,681 26,132 10,605 5,034 83,452 Rental equipment acquisitions 34,526 58,781 4,800 — 98,107 Accounts receivable, net (period end) 59,274 19,581 18,663 8,354 105,872 Rental equipment, at cost (period end) 775,400 262,325 309,808 — 1,347,533 Rental equipment, net book value (period end) 543,857 109,482 208,981 — 862,320 Utilization (period end) 2 77.8 % 61.7 % 57.5 % Average utilization 2 76.8 % 62.9 % 56.0 % Segment Data (Continued) (dollar amounts in thousands) Mobile Modular TRS- RenTelco Adler Tanks Enviroplex 1 Consolidated Year Ended December 31, 2016 Rental revenues $ 130,496 $ 82,307 $ 58,585 $ — $ 271,388 Rental related services revenues 49,206 2,846 23,807 — 75,859 Sales and other revenues 29,810 23,464 1,438 22,121 76,833 Total revenues 209,512 108,617 83,830 22,121 424,080 Depreciation of rental equipment 21,001 35,256 15,940 — 72,197 Gross profit 93,816 45,797 37,409 7,145 184,167 Selling and administrative expenses 51,432 21,896 27,610 3,970 104,908 Income from operations 42,384 23,901 9,799 3,175 79,259 Interest expense (income) allocation (6,804 ) (2,465 ) (3,200 ) 262 (12,207 ) Income before provision for income taxes 35,580 21,315 6,599 3,437 66,931 Rental equipment acquisitions 43,099 30,505 1,030 — 74,634 Accounts receivable, net (period end) 55,916 19,506 16,150 5,305 96,877 Rental equipment, at cost (period end) 744,099 245,700 306,701 — 1,324,057 Rental equipment, net book value (period end) 544,421 90,172 221,778 — 856,371 Utilization (period end) 2 77.3 % 61.0 % 50.7 % Average utilization 2 76.6 % 60.6 % 50.1 % 2015 Rental revenues $ 115,986 $ 89,208 $ 68,502 $ — $ 273,696 Rental related services revenues 45,616 3,055 24,643 — 73,314 Sales and other revenues 22,682 22,754 1,486 10,612 57,534 Total revenues 184,284 115,017 94,631 10,612 404,544 Depreciation of rental equipment 19,246 39,974 15,993 — 75,213 Gross profit 78,771 47,836 47,397 2,903 176,907 Selling and administrative expenses 46,496 22,930 27,494 3,030 99,950 Income from operations 32,275 24,906 19,903 (127 ) 76,957 Interest expense (income) allocation (5,363 ) (2,194 ) (2,729 ) 194 (10,092 ) Income before provision for income taxes 26,912 22,224 17,174 67 66,377 Rental equipment acquisitions 79,622 44,316 9,440 — 133,378 Accounts receivable, net (period end) 53,550 21,784 17,955 1,728 95,017 Rental equipment, at cost (period end) 736,875 262,945 310,263 — 1,310,083 Rental equipment, net book value (period end) 529,483 102,191 237,927 — 869,601 Utilization (period end) 2 76.9 % 58.7 % 49.7 % Average utilization 2 75.8 % 60.5 % 58.3 % 1 Gross Enviroplex sales revenues were $31,369, $22,206 and $11,530 in 2017, 2016 and 2015, respectively, which includes inter-segment sales to Mobile Modular of $0, $85 and $918, which have been eliminated in consolidation. 2 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. No single customer accounted for more than 10% of total revenues during 2017, 2016 and 2015. Revenue from foreign country customers accounted for 4%, 5% and 5% of the Company’s revenues for the same periods, respectively.

Quarterly Financial Information

Quarterly Financial Information	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information	NOTE 11. QUARTERLY FINANCIAL INFORMATION (unaudited) Quarterly financial information for each of the two years ended December 31, 2017 is summarized below: (in thousands, except per share amounts) 2017 First Second Third Fourth Year Operations Data Rental revenues $ 67,978 $ 69,953 $ 73,781 $ 77,705 $ 289,417 Total revenues 94,837 109,582 135,388 122,227 462,034 Gross profit 43,670 49,211 58,775 54,689 206,345 Income from operations 15,822 21,846 30,286 26,786 94,740 Income before (benefit) provision for income taxes 13,259 18,908 27,336 23,949 83,452 Net income 7,973 11,461 16,762 117,724 153,920 Earnings per share: Basic $ 0.33 $ 0.48 $ 0.70 $ 4.90 $ 6.41 Diluted $ 0.33 $ 0.48 $ 0.69 $ 4.82 $ 6.34 Dividends declared per share $ 0.260 $ 0.260 $ 0.260 $ 0.260 $ 1.04 Shares used in per share calculations: Basic 23,950 23,985 24,015 24,044 23,999 Diluted 24,232 24,092 24,228 24,410 24,269 Balance Sheet Data Rental equipment, net $ 856,981 $ 863,207 $ 865,724 $ 862,320 $ 862,320 Total assets 1,130,734 1,150,123 1,156,415 1,147,854 1,147,854 Notes payable 323,483 330,287 323,117 303,414 303,414 Shareholders’ equity 396,625 402,365 412,782 524,184 524,184 2016 First Second Third Fourth Year Operations Data Rental revenues $ 66,532 $ 66,747 $ 67,757 $ 70,352 $ 271,388 Total revenues 93,699 103,105 121,993 105,283 424,080 Gross profit 40,655 43,756 50,433 49,323 184,167 Income from operations 14,258 18,073 24,232 22,696 79,259 Income before provision for income taxes 10,853 15,006 21,277 19,795 66,931 Net income 6,566 9,079 12,872 9,734 38,251 Earnings per share: Basic $ 0.28 $ 0.38 $ 0.54 $ 0.41 $ 1.60 Diluted $ 0.27 $ 0.38 $ 0.54 $ 0.40 $ 1.60 Dividends declared per share $ 0.255 $ 0.255 $ 0.255 $ 0.255 $ 1.02 Shares used in per share calculations: Basic 23,862 23,900 23,911 23,927 23,900 Diluted 23,911 23,949 24,041 24,123 23,976 Balance Sheet Data Rental equipment, net $ 867,215 $ 868,422 $ 862,528 $ 856,371 $ 856,371 Total assets 1,132,355 1,148,018 1,144,923 1,128,276 1,128,276 Notes payable 365,772 363,121 345,286 326,266 326,266 Shareholders’ equity 380,512 383,313 390,600 394,287 394,287

Summary of Significant Accoun20

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
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 Rental revenue from operating leases is recognized on a straight-line basis over the term of the lease. Rental billings for periods extending beyond period end are recorded as deferred income and are recognized when earned. Rental related services revenue is primarily associated with relocatable modular building and liquid and solid containment tanks and boxes leases. For modular building leases, rental related services revenue consists of billings to customers for modifications, delivery, installation, additional site-related work, and dismantle and return delivery. For modular building leases, revenue related to delivery, installation, dismantle and return delivery are an integral part of the negotiated lease agreement with customers and are recognized on a straight-line basis over the term of the lease. For liquid and solid containment solutions, rental related services revenue consists of billings for delivery, removal and cleaning of the tanks and boxes. These revenues are recognized in the period performed. 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 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. The Company recorded an impairment of modular rental equipment of $1.6 million for the year ended December 31, 2017. There were no impairments of long-lived assets during the years ended December 31, 2016 and 2015.
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 warranties on equipment manufactured by Enviroplex. Although the Company’s policy is to provide reserves for warranties when required for specific circumstances, the Company has not found it necessary to establish such reserves to date as warranty costs have not been significant.
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 expenses 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 2017 2016 Land Indefinite $ 50,689 $ 45,928 Land improvements 20 – 50 43,337 42,677 Buildings 30 26,862 26,105 Furniture, office and computer equipment 3 – 10 32,118 35,215 Vehicles and machinery 5 – 25 34,597 30,416 187,603 180,341 Less accumulated depreciation (70,034 ) (68,854 ) 117,569 111,487 Construction in progress 1,601 703 $ 119,170 $ 112,190 Property, plant and equipment depreciation expense was $7.6 million, $8.1 million and $8.2 million for the years ended December 31, 2017, 2016 and 2015, respectively. Construction in progress at December 31, 2017 and 2016 consisted primarily of costs related to acquisition of land and 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 $0.8 million and $0.2 million in internal use software during the years ended December 31, 2017 and 2016, respectively.
Advertising Costs	Advertising Costs Advertising costs are expensed as incurred. Total advertising expenses were $2.9 million, $2.9 million and $2.8 million for the years ended December 31, 2017, 2016 and 2015.
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 have been 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 were allocated to goodwill and other intangible assets. Intangible assets related to customer relationships are amortized over eleven years. At December 31, 2017 and 2016, goodwill and trade name intangible assets which have indefinite lives totaled $33.5 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 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 and indefinite lived assets 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 as a basis for determining whether it is necessary to perform the two-step goodwill impairment test. In the first step, the fair value of the reporting unit is compared to its carrying value to determine if the goodwill and intangible assets are impaired. If the fair value of the reporting unit exceeds the carrying value of the net assets assigned to that unit, then goodwill and intangible assets are not impaired and no further testing is required. If the carrying value of the net assets assigned to the reporting unit were to exceed its fair value, then the second step is performed in order to determine the implied fair value of the reporting unit’s goodwill and intangible assets and an impairment loss is recorded for an amount equal to the difference between the implied fair value and the carrying value of the goodwill and intangible assets. The Company conducted its annual impairment analysis in the fourth quarter of its fiscal year. The impairment analysis did not result in an impairment charge for the fiscal years ended 2017, 2016 or 2015. 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, 2017 2016 2015 Weighted-average common stock for calculating basic earnings per share 23,999 23,900 25,369 Effect of potentially dilutive securities from equity-based compensation 270 76 88 Weighted-average common stock for calculating diluted earnings per share 24,269 23,976 25,457 The following securities were not included in the computation of diluted earnings per share as their effect would have been anti-dilutive: (in thousands) Year Ended December 31, 2017 2016 2015 Options to purchase common stock 7 661 746 In May 2008, the Company’s Board of Directors authorized the Company to repurchase an aggregate of 2,000,000 shares of the Company's outstanding common stock. 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 an additional 2,000,000 shares of the Company's outstanding common stock. 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 no repurchases of common stock during the twelve months ended December 31, 2017 and 2016. As of December 31, 2017, 1,592,026 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 $30.1 million at December 31, 2017 and $28.1 million at December 31, 2016. 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) 2017 2016 Beginning balance, January 1 $ 2,087 $ 2,087 Provision for doubtful accounts 1,480 1,892 Write-offs, net of recoveries (1,647 ) (1,892 ) Ending balance, December 31 $ 1,920 $ 2,087 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 $120.2 million and $140.7 million compared to the recorded value of $120.0 million and $140.0 million as of December 31, 2017 and 2016, 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”), functions 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. The Company records share-based compensation costs in “Selling and administrative expenses” in the Consolidated Statements of Income. The Company recognizes a benefit from share-based compensation in the Consolidated Statements of Shareholders’ Equity if an incremental tax benefit is realized. Further information regarding share-based compensation can be found in “Note 5 –Benefit Plans”.
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.
Reclassification	Reclassification In order to conform to our current year presentation, $2.7 million and $2.4 million were reclassified in 2016 and 2015, respectively, from other to rental related services within the direct costs of rental operations on the Condensed Consolidated Statements of Income. These reclassifications had no impact on net income, earnings per share or operating cash flows.
New Accounting Pronouncements	New Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers (Topic 606). The objective of this guidance is to establish the principles for reporting useful information to users of financial statements about the nature, timing and uncertainty of revenue from contracts with customers. The new standard is effective for the interim and annual reporting periods beginning after December 31, 2017. The new standard permits two methods of adoption: retrospectively to each prior period presented (full retrospective method), or retrospectively with the cumulative effect of initially applying the guidance recognized at the date of initial application (modified retrospective method). The Company will adopt the guidance effective January 1, 2018 using the modified retrospective method. The Company believes the majority of its revenue, as such revenue relates to rental contractual revenue, is excluded from the scope of this standard, and the remaining revenue streams will not be materially affected. The Company does not anticipate the adoption of this guidance will have a material impact on the Company’s consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases (Subtopic 842-10). Under the new guidance, lessees will be required to recognize the following for all leases (with the exception of short-term leases) on the commencement date: a) lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and During the first quarter 2017, the Company adopted ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting (ASU 2016-09). As a result of the adoption, the Company recognized $869,000 of excess tax benefits related to share-based payments as a reduction to the provision for income taxes for the year ended December 31, 2017. These tax benefits, or shortfalls, were historically recorded in equity. In addition, cash flows related to excess tax benefits, or shortfalls, are now classified as an operating activity with the prior period adjusted accordingly. Cash paid on employees’ behalf related to shares withheld for tax purposes is classified as a financing activity, consistent with prior year’s presentation. Retrospective application of the cash flow presentation requirements resulted in decreases to both net cash provided by operations and net cash used in financing activities of $1,066,000 for the twelve months ended December 31, 2016. The Company’s compensation expense for each period continues to reflect forfeitures as they occur, rather than based upon estimated expected forfeitures. In May 2017, the FASB issued ASU No. 2017-09, Compensation, Stock Compensation (Topic 718). The amendments in this update provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718.
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 Accoun21

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
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 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 2017 2016 Land Indefinite $ 50,689 $ 45,928 Land improvements 20 – 50 43,337 42,677 Buildings 30 26,862 26,105 Furniture, office and computer equipment 3 – 10 32,118 35,215 Vehicles and machinery 5 – 25 34,597 30,416 187,603 180,341 Less accumulated depreciation (70,034 ) (68,854 ) 117,569 111,487 Construction in progress 1,601 703 $ 119,170 $ 112,190
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, 2017 2016 2015 Weighted-average common stock for calculating basic earnings per share 23,999 23,900 25,369 Effect of potentially dilutive securities from equity-based compensation 270 76 88 Weighted-average common stock for calculating diluted earnings per share 24,269 23,976 25,457
Securities Not Included in Computation of Diluted Earnings Per Share	The following securities were not included in the computation of diluted earnings per share as their effect would have been anti-dilutive: (in thousands) Year Ended December 31, 2017 2016 2015 Options to purchase common stock 7 661 746
Summary of Allowance for Doubtful Accounts Activity	The allowance for doubtful accounts activity was as follows: (in thousands) 2017 2016 Beginning balance, January 1 $ 2,087 $ 2,087 Provision for doubtful accounts 1,480 1,892 Write-offs, net of recoveries (1,647 ) (1,892 ) Ending balance, December 31 $ 1,920 $ 2,087

Financed Lease Receivables (Tab

Financed Lease Receivables (Tables)	12 Months Ended
	Dec. 31, 2017
Leases [Abstract]
Minimum Lease Payments Receivable and Net Investment Included in Accounts Receivable for Leases	The minimum lease payments receivable and the net investment included in accounts receivable for such leases are as follows: (in thousands) December 31, 2017 2016 Gross minimum lease payments receivable $ 2,150 $ 3,252 Less – unearned interest (201 ) (301 ) Net investment in sales type lease receivables $ 1,949 $ 2,951
Future Minimum Lease Payments under Non-Cancelable Sales-Type Leases	As of December 31, 2017, the future minimum lease payments under non-cancelable sales-type leases to be received in 2018 and thereafter are as follows: (in thousands) Year Ended December 31, 2018 $ 1,354 2019 633 2020 163 Total minimum future lease payments $ 2,150

Notes Payable (Tables)

Notes Payable (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Components of Notes Payable	Notes payable consists of the following: (in thousands) December 31, 2017 2016 Unsecured revolving lines of credit $ 183,473 $ 186,376 4.03% Series A senior notes due in 2018 20,000 40,000 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 $ 303,473 $ 326,376
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, 2017, the future minimum payments under the unsecured revolving lines of credit, 4.03% Series A senior notes due in 2018, 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, 2018 $ 20,000 2019 — 2020 — 2021 223,473 2022 60,000 $ 303,473
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, 2017 2016 Maximum amount outstanding $ 215,732 $ 239,820 Average amount outstanding $ 199,499 $ 214,446 Weighted average interest rate, during the period 2.64 % 2.19 % Prime interest rate, end of period 4.50 % 3.75 %

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Schedule of Income Before (Benefit) Provision For Income Taxes	Income before (benefit) provision for income taxes consisted of the following: (in thousands) Year Ended December 31, 2017 2016 2015 U.S. $ 83,525 $ 67,199 $ 66,889 Foreign (73 ) (268 ) (512 ) $ 83,452 $ 66,931 $ 66,377
(Benefit) Provision for Income Taxes	The (benefit) provision for income taxes consisted of the following: (in thousands) Year Ended December 31, 2017 2016 2015 Current: U.S. Federal $ 21,171 $ 17,203 $ 7,976 State 2,976 2,049 1,851 Foreign 2,016 1,683 1,645 26,163 20,935 11,472 Deferred: U.S. Federal (103,518 ) 4,005 13,201 State 6,948 3,039 1,538 Foreign (61 ) 701 (304 ) (96,631 ) 7,745 14,435 Total $ (70,468 ) $ 28,680 $ 25,907
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, 2017 2016 2015 U.S. federal statutory rate 35.0 % 35.0 % 35.0 % State taxes, net of federal benefit 4.1 4.2 4.2 State deferred tax rate change, net of federal benefit 0.5 2.0 (0.4 ) Valuation allowance 0.1 1.1 — Share-based compensation (1.0 ) — — Enactment of the Tax Cuts and Jobs Act (122.9 ) — — Other (0.2 ) 0.6 0.2 (84.4 )% 42.9 % 39.0 %
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, 2017 2016 Deferred tax liabilities: Accelerated depreciation $ 195,694 $ 293,141 Prepaid costs currently deductible 4,152 6,572 Other 4,405 5,747 Total deferred tax liabilities 204,251 305,460 Deferred tax assets: Accrued costs not yet deductible 7,880 9,785 Allowance for doubtful accounts 484 809 Deferred revenues 213 965 Share-based compensation 1,045 1,882 Total deferred tax assets, net of valuation allowance of $0.8 million in 2017 and $0.7 million in 2016 9,622 13,441 Deferred income taxes, net $ 194,629 $ 292,019

Benefit Plans (Tables)

Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2017
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, 2017 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, 2014 1,343,760 $ 27.25 Options granted 456,200 31.69 Options exercised (270,650 ) 19.81 Options cancelled/forfeited/expired (118,660 ) 29.58 Balance at December 31, 2015 1,410,650 29.91 Options granted 881,800 25.26 Options exercised (368,085 ) 27.34 Options cancelled/forfeited/expired (339,930 ) 28.62 Balance at December 31, 2016 1,584,435 28.14 Options granted 299,600 34.66 Options exercised (398,275 ) 28.94 Options cancelled/forfeited/expired (276,900 ) 28.04 Balance at December 31, 2017 1,208,860 $ 29.52 4.94 $ 21.1 Exercisable at December 31, 2017 325,680 $ 28.65 4.04 $ 6.0 Expected to vest after December 31, 2017 680,049 $ 29.78 5.28 $ 11.7
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, 2017: 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, 2017 Weighted- average grant date value $20 – 25 481,510 5.13 $ 24.59 125,505 $ 24.58 $25 – 30 57,505 3.14 $ 28.05 37,300 $ 28.91 $30 – 35 654,265 4.94 $ 33.07 160,635 $ 32.09 $35 – 40 8,780 5.32 $ 38.61 2,240 $ 38.18 $40 – 45 6,800 6.67 $ 40.37 — $ — $20 – 45 1,208,860 4.94 $ 29.52 325,680 $ 28.65
Schedule of Weighted-Average Assumptions Used to Determine Fair Value of Option Granted	The fair value of each option granted was estimated on the date of grant using the Black-Scholes option-pricing model using the following weighted-average assumptions: Year Ended December 31, 2017 2016 2015 Expected term (in years) 5.0 5.0 5.0 Expected volatility 26.1 % 28.7 % 31.1 % Expected dividend yields 3.0 % 4.1 % 3.2 % Risk-free interest rates 2.0 % 1.2 % 1.6 %
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, 2017: Weighted- Aggregate average intrinsic Number grant date value of shares fair value (in millions) Balance at December 31, 2014 311,583 $ 29.78 RSUs granted 79,300 31.86 RSUs vested (89,915 ) 27.97 RSUs cancelled/forfeited/expired (80,320 ) 31.35 Balance at December 31, 2015 220,648 30.70 RSUs granted 31,900 25.75 RSUs vested (59,008 ) 29.69 RSUs cancelled/forfeited/expired (68,300 ) 29.33 Balance at December 31, 2016 125,240 30.66 RSUs granted 70,960 34.53 RSUs vested (36,336 ) 26.99 RSUs cancelled/forfeited/expired (66,200 ) 32.63 Balance at December 31, 2017 93,664 $ 33.62 $ 4.4

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
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, 2018 $ 1,632 2019 1,282 2020 941 2021 839 2022 863 Thereafter 1,964 $ 7,521

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Intangible Assets	Intangible assets consist of the following: (dollar amounts in thousands) Estimated useful life December 31, (In years) 2017 2016 Trade name Indefinite $ 5,700 $ 5,700 Customer relationships 11 9,611 9,611 15,311 15,311 Less accumulated amortization (7,587 ) (6,716 ) $ 7,724 $ 8,595

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Summarized Financial Information for Company's Reportable Segments	Summarized financial information for the years ended December 31, 2017, 2016 and 2015, for the Company’s reportable segments is shown in the following tables: Segment Data (dollar amounts in thousands) Mobile Modular TRS- RenTelco Adler Tanks Enviroplex 1 Consolidated Year Ended December 31, 2017 Rental revenues $ 142,584 $ 82,812 $ 64,021 $ — $ 289,417 Rental related services revenues 50,448 2,858 24,762 — 78,068 Sales and other revenues 38,234 22,374 2,572 31,369 94,549 Total revenues 231,266 108,044 91,355 31,369 462,034 Depreciation of rental equipment 21,247 32,891 15,770 — 69,908 Gross profit 103,935 50,289 43,218 8,903 206,345 Selling and administrative expenses 55,583 22,171 29,542 4,309 111,605 Income from operations 48,352 28,118 13,676 4,594 94,740 Interest expense (income) allocation (6,671 ) (2,320 ) (3,071 ) 440 (11,622 ) Income before (benefit) provision for income taxes 41,681 26,132 10,605 5,034 83,452 Rental equipment acquisitions 34,526 58,781 4,800 — 98,107 Accounts receivable, net (period end) 59,274 19,581 18,663 8,354 105,872 Rental equipment, at cost (period end) 775,400 262,325 309,808 — 1,347,533 Rental equipment, net book value (period end) 543,857 109,482 208,981 — 862,320 Utilization (period end) 2 77.8 % 61.7 % 57.5 % Average utilization 2 76.8 % 62.9 % 56.0 % Segment Data (Continued) (dollar amounts in thousands) Mobile Modular TRS- RenTelco Adler Tanks Enviroplex 1 Consolidated Year Ended December 31, 2016 Rental revenues $ 130,496 $ 82,307 $ 58,585 $ — $ 271,388 Rental related services revenues 49,206 2,846 23,807 — 75,859 Sales and other revenues 29,810 23,464 1,438 22,121 76,833 Total revenues 209,512 108,617 83,830 22,121 424,080 Depreciation of rental equipment 21,001 35,256 15,940 — 72,197 Gross profit 93,816 45,797 37,409 7,145 184,167 Selling and administrative expenses 51,432 21,896 27,610 3,970 104,908 Income from operations 42,384 23,901 9,799 3,175 79,259 Interest expense (income) allocation (6,804 ) (2,465 ) (3,200 ) 262 (12,207 ) Income before provision for income taxes 35,580 21,315 6,599 3,437 66,931 Rental equipment acquisitions 43,099 30,505 1,030 — 74,634 Accounts receivable, net (period end) 55,916 19,506 16,150 5,305 96,877 Rental equipment, at cost (period end) 744,099 245,700 306,701 — 1,324,057 Rental equipment, net book value (period end) 544,421 90,172 221,778 — 856,371 Utilization (period end) 2 77.3 % 61.0 % 50.7 % Average utilization 2 76.6 % 60.6 % 50.1 % 2015 Rental revenues $ 115,986 $ 89,208 $ 68,502 $ — $ 273,696 Rental related services revenues 45,616 3,055 24,643 — 73,314 Sales and other revenues 22,682 22,754 1,486 10,612 57,534 Total revenues 184,284 115,017 94,631 10,612 404,544 Depreciation of rental equipment 19,246 39,974 15,993 — 75,213 Gross profit 78,771 47,836 47,397 2,903 176,907 Selling and administrative expenses 46,496 22,930 27,494 3,030 99,950 Income from operations 32,275 24,906 19,903 (127 ) 76,957 Interest expense (income) allocation (5,363 ) (2,194 ) (2,729 ) 194 (10,092 ) Income before provision for income taxes 26,912 22,224 17,174 67 66,377 Rental equipment acquisitions 79,622 44,316 9,440 — 133,378 Accounts receivable, net (period end) 53,550 21,784 17,955 1,728 95,017 Rental equipment, at cost (period end) 736,875 262,945 310,263 — 1,310,083 Rental equipment, net book value (period end) 529,483 102,191 237,927 — 869,601 Utilization (period end) 2 76.9 % 58.7 % 49.7 % Average utilization 2 75.8 % 60.5 % 58.3 % 1 Gross Enviroplex sales revenues were $31,369, $22,206 and $11,530 in 2017, 2016 and 2015, respectively, which includes inter-segment sales to Mobile Modular of $0, $85 and $918, which have been eliminated in consolidation. 2 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.

Quarterly Financial Informati29

Quarterly Financial Information (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information	Quarterly financial information for each of the two years ended December 31, 2017 is summarized below: (in thousands, except per share amounts) 2017 First Second Third Fourth Year Operations Data Rental revenues $ 67,978 $ 69,953 $ 73,781 $ 77,705 $ 289,417 Total revenues 94,837 109,582 135,388 122,227 462,034 Gross profit 43,670 49,211 58,775 54,689 206,345 Income from operations 15,822 21,846 30,286 26,786 94,740 Income before (benefit) provision for income taxes 13,259 18,908 27,336 23,949 83,452 Net income 7,973 11,461 16,762 117,724 153,920 Earnings per share: Basic $ 0.33 $ 0.48 $ 0.70 $ 4.90 $ 6.41 Diluted $ 0.33 $ 0.48 $ 0.69 $ 4.82 $ 6.34 Dividends declared per share $ 0.260 $ 0.260 $ 0.260 $ 0.260 $ 1.04 Shares used in per share calculations: Basic 23,950 23,985 24,015 24,044 23,999 Diluted 24,232 24,092 24,228 24,410 24,269 Balance Sheet Data Rental equipment, net $ 856,981 $ 863,207 $ 865,724 $ 862,320 $ 862,320 Total assets 1,130,734 1,150,123 1,156,415 1,147,854 1,147,854 Notes payable 323,483 330,287 323,117 303,414 303,414 Shareholders’ equity 396,625 402,365 412,782 524,184 524,184 2016 First Second Third Fourth Year Operations Data Rental revenues $ 66,532 $ 66,747 $ 67,757 $ 70,352 $ 271,388 Total revenues 93,699 103,105 121,993 105,283 424,080 Gross profit 40,655 43,756 50,433 49,323 184,167 Income from operations 14,258 18,073 24,232 22,696 79,259 Income before provision for income taxes 10,853 15,006 21,277 19,795 66,931 Net income 6,566 9,079 12,872 9,734 38,251 Earnings per share: Basic $ 0.28 $ 0.38 $ 0.54 $ 0.41 $ 1.60 Diluted $ 0.27 $ 0.38 $ 0.54 $ 0.40 $ 1.60 Dividends declared per share $ 0.255 $ 0.255 $ 0.255 $ 0.255 $ 1.02 Shares used in per share calculations: Basic 23,862 23,900 23,911 23,927 23,900 Diluted 23,911 23,949 24,041 24,123 23,976 Balance Sheet Data Rental equipment, net $ 867,215 $ 868,422 $ 862,528 $ 856,371 $ 856,371 Total assets 1,132,355 1,148,018 1,144,923 1,128,276 1,128,276 Notes payable 365,772 363,121 345,286 326,266 326,266 Shareholders’ equity 380,512 383,313 390,600 394,287 394,287

Summary of Significant Accoun30

Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017USD ($)DivisionSegmentshares	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)	Aug. 31, 2015shares	May 31, 2008shares
Summary Of Significant Accounting Policies [Line Items]
Number of divisions | Division	4
Number of reportable segments | Segment	4
Impairments of long-lived assets	$ 1,639,000	$ 0	$ 0
Period for warranties for rental equipment	90 days
Period for warranties for equipment manufactured	1 year
Property, plant and equipment depreciation expenses	$ 7,600,000	8,100,000	8,200,000
Capitalized in internal use of software	800,000	200,000
Total advertising expenses	$ 2,900,000	2,900,000	2,800,000
Estimated useful life in years, Customer relationships	11 years
Goodwill and trade name intangible assets	$ 33,500,000	33,500,000
Goodwill and intangible assets impairment charge	$ 0	$ 0	0
Common stock shares authorized for repurchase | shares				2,000,000	2,000,000
Common stock repurchased | shares	0	0
Shares remain authorized for repurchase | shares	1,592,026
Unbilled receivables related to end-of-lease services	$ 30,100,000	$ 28,100,000
Period for credit risk identified	30 days
Estimated fair value notes payable	$ 120,200,000	140,700,000
Recorded fair value of notes payable	120,000,000	140,000,000
Prior period reclassification adjustment		2,700,000	$ 2,400,000
ASU 2016-09 [Member]
Summary Of Significant Accounting Policies [Line Items]
Excess tax benefits related to share-based payments	869,000
Decrease in net cash provided by operations and net cash used in financing activities due to retrospective application of new accounting standard		$ 1,066,000
Modular Rental Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairments of long-lived assets	$ 1,600,000

Summary of Significant Accoun31

Summary of Significant Accounting Policies - Estimated Useful Lives and Residual Values of Company's Rental Equipment (Detail)	12 Months Ended
	Dec. 31, 2017
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%
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 Accoun32

Summary of Significant Accounting Policies - Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 187,603	$ 180,341
Less accumulated depreciation	(70,034)	(68,854)
Property plant and equipment net excluding capitalized cost	117,569	111,487
Construction in progress	1,601	703
Property, Plant and Equipment, net	119,170	112,190
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 50,689	45,928
Estimated useful life	Indefinite
Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 43,337	42,677
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	$ 26,862	26,105
Estimated useful life	30 years
Furniture, Office and Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 32,118	35,215
Furniture, Office and Computer Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Furniture, Office and Computer Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Vehicles and Machinery [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 34,597	$ 30,416
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 Accoun33

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, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Weighted-average common stock for calculating basic earnings per share	24,044	24,015	23,985	23,950	23,927	23,911	23,900	23,862	23,999	23,900	25,369
Effect of potentially dilutive securities from equity-based compensation									270	76	88
Weighted-average common stock for calculating diluted earnings per share	24,410	24,228	24,092	24,232	24,123	24,041	23,949	23,911	24,269	23,976	25,457

Summary of Significant Accoun34

Summary of Significant Accounting Policies - Securities Not Included in Computation of Diluted Earnings Per Share (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Options to purchase common stock	7	661	746

Summary of Significant Accoun35

Summary of Significant Accounting Policies - Summary of Allowance for Doubtful Accounts Activity (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Allowance for doubtful accounts, Beginning Balance	$ 2,087	$ 2,087
Provision for doubtful accounts	1,480	1,892	$ 2,149
Write-offs, net of recoveries	(1,647)	(1,892)
Allowance for doubtful accounts, Ending Balance	$ 1,920	$ 2,087	$ 2,087

Financed Lease Receivables - Mi

Financed Lease Receivables - Minimum Lease Payments Receivable and Net Investment Included in Accounts Receivable for Leases (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Minimum lease payments receivable and net investment included in accounts receivable for leases
Gross minimum lease payments receivable	$ 2,150	$ 3,252
Less – unearned interest	(201)	(301)
Net investment in sales type lease receivables	$ 1,949	$ 2,951

Financed Lease Receivables - Fu

Financed Lease Receivables - Future Minimum Lease Payments under Non-Cancelable Sales-Type Leases (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Future minimum lease payments under non-cancelable sales-type leases
2,018	$ 1,354
2,019	633
2,020	163
Total minimum future lease payments	$ 2,150	$ 3,252

Notes Payable - Components of N

Notes Payable - Components of Notes Payable (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Notes payable	$ 303,473	$ 326,376
Unsecured Revolving Lines of Credit [Member]
Debt Instrument [Line Items]
Notes payable	183,473	186,376
Series A senior notes [Member] | 4.03% Series A senior notes due in 2018 [Member]
Debt Instrument [Line Items]
Notes payable	20,000	40,000
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 of39

Notes Payable - Components of Notes Payable (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2017	Nov. 05, 2015	Mar. 17, 2014	Apr. 21, 2011
Series A senior notes [Member] | 4.03% Series A senior notes due in 2018 [Member]
Debt Instrument [Line Items]
Senior Notes, interest rate	4.03%			4.03%
Senior Notes, year of maturity	2,018
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	2,021
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	2,022

Notes Payable - Schedule of Fut

Notes Payable - 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 (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Notes payable	$ 303,473	$ 326,376
Notes Payable to Banks and Others [Member]
Debt Instrument [Line Items]
2,018	20,000
2,021	223,473
2,022	60,000
Notes payable	$ 303,473

Notes Payable - Additional Info

Notes Payable - Additional Information (Detail) - USD ($)	Nov. 05, 2015	Mar. 17, 2014	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Feb. 09, 2016	Apr. 21, 2011
Debt Instrument [Line Items]
Consolidated Fixed Charge Coverage Ratio			2.50%
Consolidated Fixed Charge Coverage Ratio, actual			6.82%
Consolidated Leverage Ratio			2.75%
Consolidated Leverage Ratio, actual			1.70%
Line of credit facility covenants tangible net worth description			Permit Tangible Net Worth, calculated as of the last day of each fiscal quarter, to be less than the sum of (i) $229.0 million, plus (ii) 25% of net income for such fiscal quarter subsequent to December 31, 2010, plus (iii) 90% of the net cash proceeds from the issuance of the Company’s capital stock after December 31, 2010.
Tangible Net Worth sum			$ 349,900,000
Consolidated Net Income			25.00%
Percentage of net cash proceeds from issuance of capital stock			90.00%
Actual tangible net worth			$ 488,700,000
Senior notes principal balance outstanding			$ 303,473,000	$ 326,376,000
2016 Amendment [Member]
Debt Instrument [Line Items]
Senior notes description			(i) the issuance period for the shelf notes to be issued and sold pursuant to the Note Purchase Agreement is extended until the earlier of February 9, 2019 or the termination of the issuance and sale of the shelf notes upon the 30 days’ prior notice of either PIM or the Company, and (ii) the definition of the “Available Facility Amount,” which is the aggregate amount of the shelf notes that may be authorized for purchase pursuant to the Note Purchase Agreement was amended to equal a formula based on: $250 million, minus the aggregate principal amount of the shelf notes then outstanding and purchased pursuant to the Note Purchase Agreement, minus the shelf notes accepted by the Company for purchase, but not yet purchased, by the Purchaser pursuant to the Note Purchase Agreement; provided, however, the aggregate amount of the shelf notes purchased by any corporation or other entity controlling, controlled by, or under common control with, PIM shall not exceed $200 million.
Stated formula value for determining available facility amount						$ 250,000,000
Series A senior notes [Member] | 4.03% Series A senior notes due in 2018 [Member]
Debt Instrument [Line Items]
Aggregate principal amount							$ 100,000,000
Senior notes interest rate			4.03%				4.03%
Debt instrument, payment terms			Interest on these notes is due semi-annually in arrears and the principal is due in five equal annual installments, with the first payment due on April 21, 2014.
Debt instrument, maturity date			Apr. 21, 2018
Debt instrument, date of first required payment			Apr. 21, 2014
Senior notes principal balance outstanding			$ 20,000,000	40,000,000
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%
Debt instrument, maturity date			Mar. 17, 2021
Senior notes principal balance outstanding			$ 40,000,000	40,000,000
Proceeds from issuance of senior notes		$ 40,000,000
Senior notes description			The Series B Senior Notes are an unsecured obligation of the Company, 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.
Senior notes interest payment			Semi-annually
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%
Debt instrument, payment terms			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.
Debt instrument, maturity date			Nov. 5, 2022
Debt instrument, date of first required payment			May 5, 2016
Senior notes principal balance outstanding			$ 60,000,000	$ 60,000,000
Proceeds from issuance of senior notes	$ 60,000,000
Senior notes interest payment			Semi-annually
Minimum [Member]
Debt Instrument [Line Items]
Tangible Net Worth sum			$ 229,000,000
Maximum [Member] | 2016 Amendment [Member]
Debt Instrument [Line Items]
Aggregate principal amount						$ 200,000,000
Credit Facility [Member]
Debt Instrument [Line Items]
Revolving credit facility, maturity period			5 years
Revolving credit facility, maturity date			Mar. 31, 2021
Credit facility, maximum			$ 420,000,000
Revolving credit facility, available maximum borrowing capacity			620,000,000
Additional commitments			$ 200,000,000
Consolidated Fixed Charge Coverage Ratio			2.50%
Consolidated Fixed Charge Coverage Ratio, actual			6.82%
Consolidated Leverage Ratio			2.75%
Consolidated Leverage Ratio, actual			1.70%
Line of credit facility covenants tangible net worth description			Permit Tangible Net Worth as of the end of any fiscal quarter of the Company to be less than the sum of (i) $246.1 million plus (ii) 25% of the Company’s Consolidated Net Income (as defined in the Amended Credit Facility) (but only if a positive number) for each fiscal quarter ended subsequent to December 31, 2011
Tangible Net Worth sum			$ 349,900,000
Consolidated Net Income			25.00%
Percentage of net cash proceeds from issuance of capital stock			90.00%
Actual tangible net worth			$ 488,700,000
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, 2017 and 2016, the applicable margins were 1.25% and 1.50% for LIBOR based loans, respectively, 0.25% and 0.50% for base rate loans, respectively and 0.20% and 0.25% for unused fees, respectively. 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%	0.25%
Credit Facility [Member] | LIBOR Loans [Member]
Debt Instrument [Line Items]
Debt instrument interest rate at period end			1.25%	1.50%
Credit Facility [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt instrument interest rate at period end			0.25%	0.50%
Credit Facility [Member] | Sweep Service Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum			$ 432,000,000
Revolving credit facility, available maximum borrowing capacity			248,500,000
Amount outstanding			183,500,000
Unused commitment fees			12,000,000
Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Tangible Net Worth sum			$ 246,100,000
Leverage ratio			0.15%
Credit Facility [Member] | Minimum [Member] | LIBOR Loans [Member]
Debt Instrument [Line Items]
Leverage ratio			1.00%
Credit Facility [Member] | Minimum [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Leverage ratio			0.00%
Credit Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio			0.30%
Credit Facility [Member] | Maximum [Member] | LIBOR Loans [Member]
Debt Instrument [Line Items]
Leverage ratio			1.75%
Credit Facility [Member] | Maximum [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Leverage ratio			0.75%
Unsecured revolving credit facility before Renewal [Member]
Debt Instrument [Line Items]
Credit facility, maximum			$ 420,000,000
Letters of Credit [Member]
Debt Instrument [Line Items]
Credit facility, maximum			25,000,000
Letters of Credit [Member] | Minimum [Member]
Debt Instrument [Line Items]
Credit facility, maximum					$ 10,000,000
Letters of Credit [Member] | Maximum [Member]
Debt Instrument [Line Items]
Credit facility, maximum					$ 12,000,000
Swingline Loans [Member]
Debt Instrument [Line Items]
Credit facility, maximum			$ 10,000,000

Notes Payable - Schedule of Inf

Notes Payable - Schedule of Information Related to Lines of Credit (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
Maximum amount outstanding	$ 215,732	$ 239,820
Average amount outstanding	$ 199,499	$ 214,446
Weighted average interest rate, during the period	2.64%	2.19%
Prime interest rate, end of period	4.50%	3.75%

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income Before (Benefit) Provision For Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest [Abstract]
U.S.									$ 83,525	$ 67,199	$ 66,889
Foreign									(73)	(268)	(512)
Income before provision for income taxes	$ 23,949	$ 27,336	$ 18,908	$ 13,259	$ 19,795	$ 21,277	$ 15,006	$ 10,853	$ 83,452	$ 66,931	$ 66,377

Income Taxes - (Benefit) Provis

Income Taxes - (Benefit) Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
U.S. Federal	$ 21,171	$ 17,203	$ 7,976
State	2,976	2,049	1,851
Foreign	2,016	1,683	1,645
Current income tax expense (benefit)	26,163	20,935	11,472
Deferred:
U.S. Federal	(103,518)	4,005	13,201
State	6,948	3,039	1,538
Foreign	(61)	701	(304)
Deferred income tax expense (benefit)	(96,631)	7,745	14,435
Total	$ (70,468)	$ 28,680	$ 25,907

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, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
U.S. federal statutory rate	35.00%	35.00%	35.00%
State taxes, net of federal benefit	4.10%	4.20%	4.20%
State deferred tax rate change, net of federal benefit	0.50%	2.00%	(0.40%)
Valuation allowance	0.10%	1.10%
Share-based compensation	(1.00%)
Enactment of the Tax Cuts and Jobs Act	(122.90%)
Other	(0.20%)	0.60%	0.20%
Effective Income Tax Rate	(84.40%)	42.90%	39.00%

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, 2017	Dec. 31, 2016
Deferred tax liabilities:
Accelerated depreciation	$ 195,694	$ 293,141
Prepaid costs currently deductible	4,152	6,572
Other	4,405	5,747
Total deferred tax liabilities	204,251	305,460
Deferred tax assets:
Accrued costs not yet deductible	7,880	9,785
Allowance for doubtful accounts	484	809
Deferred revenues	213	965
Share-based compensation	1,045	1,882
Total deferred tax assets, net of valuation allowance of $0.8 million in 2017 and $0.7 million in 2016	9,622	13,441
Deferred income taxes, net	$ 194,629	$ 292,019

Income Taxes - Deferred Incom47

Income Taxes - Deferred Income Taxes Related to Temporary Differences between Tax Bases of Assets and Liabilities (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Deferred tax assets, valuation allowance	$ 0.8	$ 0.7

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Federal corporate tax rate		35.00%	35.00%	35.00%
Net tax benefit recognized due to re-measurement of deferred tax liabilities		$ 102,800,000
Provisional income tax expense related to deemed repatriation of foreign earnings		300,000
Deferred tax liability related to foreign earnings		$ 0
Term of finalizing provision		1 year
Excess tax shortfall (benefit) from exercise of share-based awards		$ (900,000)	$ 1,100,000	$ 300,000
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		$ 400,000
Net operating losses carryforwards, expiration year		2,023
Scenario Forecast [Member]
Operating Loss Carryforwards [Line Items]
Federal corporate tax rate	21.00%

Benefit Plans - Additional Info

Benefit Plans - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jun. 08, 2016	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 3,198,000	$ 3,091,000	$ 3,399,000
Tax benefit related to share-based compensation expense	1,300,000	1,200,000	1,300,000
Capitalized share-based compensation expense	$ 0	$ 0	$ 0
Stock option plans remain outstanding	1,208,860	1,584,435	1,410,650		1,343,760
Weighted average grant date fair value	$ 6.28	$ 4.14	$ 6.60
Eligible period of service for participation in plan	3 months
Minimum age for employees to participate in KSOP	21 years
Dividends deducted		$ 300,000
Tax benefit from dividends	$ 100,000
Shares outstanding, employee stock ownership plan	258,482
Percentage of total common shares outstanding	2.00%
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional shares authorized	2,097,594
Stock options granted	8,458,600
Stock options, exercise prices lower	$ 3.47
Stock options, exercise prices upper	$ 40.37
Purchase of shares	5,620,878
Stock option shares terminated	1,628,622
Stock option plans remain outstanding	1,208,860
Stock options outstanding, exercise prices lower	$ 23.84
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	$ 6,200,000	$ 4,200,000	$ 5,700,000
Total unrecognized compensation cost	$ 4,300,000
Expected recognition period of unrecognized compensation expense	2 years 8 months 12 days
Performance-based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options vesting period	5 years
Percentage of vesting annually at anniversary	20.00%
Number of RSU's expected to vest	112,834
Performance-based RSUs [Member] | Vesting after three years [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of vesting RSUs	60.00%
Service-based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of RSU's expected to vest	17,600
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	2 years 2 months 12 days
Number of forfeitures expected	66,200	68,300	80,320
Total fair value of RSU's vested based on weighted average grant date values	$ 1,000,000	$ 1,800,000	$ 2,500,000
Stock-based compensation expense for restricted stock	1,400,000	$ 1,000,000	$ 1,700,000
Total unrecognized compensation expense net of forfeitures	$ 1,700,000
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, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Options, Beginning Balance	1,584,435	1,410,650	1,343,760
Number of Options, granted	299,600	881,800	456,200
Number of Options, exercised	(398,275)	(368,085)	(270,650)
Number of Options, cancelled/forfeited/expired	(276,900)	(339,930)	(118,660)
Number of Options, Ending Balance	1,208,860	1,584,435	1,410,650
Number of Options, Exercisable at December 31, 2017	325,680
Number of Options, Expected to Vest after December 31, 2017	680,049
Weighted-Average Price, Beginning Balance	$ 28.14	$ 29.91	$ 27.25
Weighted-Average Price, Options granted	34.66	25.26	31.69
Weighted-Average Price, Options exercised	28.94	27.34	19.81
Weighted-Average Price, Options cancelled/forfeited/expired	28.04	28.62	29.58
Weighted-Average Price, Ending Balance	29.52	$ 28.14	$ 29.91
Weighted-Average Price, Exercisable at December 31, 2017	28.65
Weighted-Average Price, Expected to Vest after December 31, 2017	$ 29.78
Weighted-Average Remaining Contractual Term, Balance At December 31, 2017	4 years 11 months 8 days
Weighted-Average Remaining Contractual Term, Exercisable at December 31, 2017	4 years 14 days
Weighted-Average Remaining Contractual Term, Expected to Vest after December 31, 2017	5 years 3 months 10 days
Aggregate Intrinsic Value, Balance At December 31, 2017	$ 21.1
Aggregate Intrinsic Value, Exercisable at December 31, 2017	6
Aggregate Intrinsic Value, Expected to Vest after December 31, 2017	$ 11.7

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, 2017$ / 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	481,510
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	5 years 1 month 17 days
Options Outstanding, Weighted-Average Grant Date Value	$ 24.59
Options Exercisable, Number | shares	125,505
Options Exercisable, Weighted-Average Grant Date Value	$ 24.58
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	57,505
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	3 years 1 month 20 days
Options Outstanding, Weighted-Average Grant Date Value	$ 28.05
Options Exercisable, Number | shares	37,300
Options Exercisable, Weighted-Average Grant Date Value	$ 28.91
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	654,265
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	4 years 11 months 8 days
Options Outstanding, Weighted-Average Grant Date Value	$ 33.07
Options Exercisable, Number | shares	160,635
Options Exercisable, Weighted-Average Grant Date Value	$ 32.09
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	8,780
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	5 years 3 months 25 days
Options Outstanding, Weighted-Average Grant Date Value	$ 38.61
Options Exercisable, Number | shares	2,240
Options Exercisable, Weighted-Average Grant Date Value	$ 38.18
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	6,800
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	6 years 8 months 1 day
Options Outstanding, 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	1,208,860
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	4 years 11 months 8 days
Options Outstanding, Weighted-Average Grant Date Value	$ 29.52
Options Exercisable, Number | shares	325,680
Options Exercisable, Weighted-Average Grant Date Value	$ 28.65

Benefit Plans - Schedule of Wei

Benefit Plans - Schedule of Weighted-Average Assumptions Used to Determine Fair Value of Option Granted (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Expected term (in years)	5 years	5 years	5 years
Expected volatility	26.10%	28.70%	31.10%
Expected dividend yields	3.00%	4.10%	3.20%
Risk-free interest rates	2.00%	1.20%	1.60%

Benefit Plans - Summary of Co53

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, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Beginning Balance	125,240	220,648	311,583
Number of Shares, granted	70,960	31,900	79,300
Number of Shares, vested	(36,336)	(59,008)	(89,915)
Number of Shares, cancelled/forfeited/expired	(66,200)	(68,300)	(80,320)
Number of Shares, Ending Balance	93,664	125,240	220,648
Weighted-Average Grant Date Fair Value, Beginning Balance	$ 30.66	$ 30.70	$ 29.78
Weighted-Average Grant Date Fair Value, granted	34.53	25.75	31.86
Weighted-Average Grant Date Fair Value, vested	26.99	29.69	27.97
Weighted-Average Grant Date Fair Value, cancelled/forfeited/expired	32.63	29.33	31.35
Weighted-Average Grant Date Fair Value, Ending Balance	$ 33.62	$ 30.66	$ 30.70
Aggregate Intrinsic Value	$ 4.4

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Aug. 31, 2015	May 31, 2008
Stockholders Equity Note [Abstract]
Common stock shares authorized for repurchase			2,000,000	2,000,000
Shares remain authorized for repurchase	1,592,026
Common stock repurchased, Shares	0	0

Commitments and Contingencies -

Commitments and Contingencies - Minimum Payments under Leases, Exclusive of Property Taxes and Insurance (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Operating Leases Future Minimum Payments Due [Abstract]
2,018	$ 1,632
2,019	1,282
2,020	941
2,021	839
2,022	863
Thereafter	1,964
Total minimum future lease payments	$ 7,521

Commitments and Contingencies56

Commitments and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Commitments And Contingencies Disclosure [Abstract]
Rent expense	$ 3,600,000	$ 3,500,000	$ 3,500,000
Health compensation plan annual stop-loss insurance per claim	200,000
Workers compensation plan annual stop-loss insurance per claim	250,000
Accruals for health and workers' compensation plans	$ 2,900,000	$ 2,400,000

Intangible Assets - Summary of

Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Trade name	$ 5,700	$ 5,700
Customer relationships	9,611	9,611
Intangible Assets, gross	15,311	15,311
Less accumulated amortization	(7,587)	(6,716)
Intangible Assets, net	$ 7,724	$ 8,595
Estimated useful life in years, Customer relationships	11 years

Intangible Assets - Additional

Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization expense	$ 900,000	$ 900,000	$ 900,000
Subsequent impairment of the underlying assets	0
Expected annual amortization expense for 2018	900,000
Expected annual amortization expense for 2019	900,000
Expected annual amortization expense for 2020	$ 200,000

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Related Party Transactions [Abstract]
Amount due from (to) related party	$ 0	$ 0

Segment Reporting - Additional

Segment Reporting - Additional Information (Detail) - Segment	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Number of reportable segments	4
Customer Concentration Risk [Member] | Sales [Member]
Segment Reporting Information [Line Items]
Revenues from customers	10.00%	10.00%	10.00%
Geographic Concentration Risk [Member] | Sales [Member] | Foreign Country Customers [Member]
Segment Reporting Information [Line Items]
Revenues from customers	4.00%	5.00%	5.00%

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, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Rental revenues		$ 77,705	$ 73,781	$ 69,953	$ 67,978	$ 70,352	$ 67,757	$ 66,747	$ 66,532	$ 289,417	$ 271,388	$ 273,696
Rental related services revenues										78,068	75,859	73,314
Sales and other revenues										94,549	76,833	57,534
Total revenues		122,227	135,388	109,582	94,837	105,283	121,993	103,105	93,699	462,034	424,080	404,544
Depreciation of rental equipment										69,908	72,197	75,213
Gross profit		54,689	58,775	49,211	43,670	49,323	50,433	43,756	40,655	206,345	184,167	176,907
Selling and administrative expenses										111,605	104,908	99,950
Income from operations		26,786	30,286	21,846	15,822	22,696	24,232	18,073	14,258	94,740	79,259	76,957
Interest expense (income) allocation										(11,622)	(12,207)	(10,092)
Income before (benefit) provision for income taxes		23,949	27,336	18,908	13,259	19,795	21,277	15,006	10,853	83,452	66,931	66,377
Rental equipment acquisitions										98,107	74,634	133,378
Accounts receivable, net (period end)		105,872				96,877				105,872	96,877	95,017
Rental equipment, at cost (period end)		1,347,533				1,324,057				1,347,533	1,324,057	1,310,083
Rental equipment, net book value (period end)		862,320	$ 865,724	$ 863,207	$ 856,981	856,371	$ 862,528	$ 868,422	$ 867,215	862,320	856,371	869,601
Mobile Modular [Member]
Segment Reporting Information [Line Items]
Rental revenues										142,584	130,496	115,986
Rental related services revenues										50,448	49,206	45,616
Sales and other revenues										38,234	29,810	22,682
Total revenues										231,266	209,512	184,284
Depreciation of rental equipment										21,247	21,001	19,246
Gross profit										103,935	93,816	78,771
Selling and administrative expenses										55,583	51,432	46,496
Income from operations										48,352	42,384	32,275
Interest expense (income) allocation										(6,671)	(6,804)	(5,363)
Income before (benefit) provision for income taxes										41,681	35,580	26,912
Rental equipment acquisitions										34,526	43,099	79,622
Accounts receivable, net (period end)		59,274				55,916				59,274	55,916	53,550
Rental equipment, at cost (period end)		775,400				744,099				775,400	744,099	736,875
Rental equipment, net book value (period end)		543,857				544,421				$ 543,857	$ 544,421	$ 529,483
Utilization (period end)	[1]									77.80%	77.30%	76.90%
Average utilization	[1]									76.80%	76.60%	75.80%
TRS-RenTelco [Member]
Segment Reporting Information [Line Items]
Rental revenues										$ 82,812	$ 82,307	$ 89,208
Rental related services revenues										2,858	2,846	3,055
Sales and other revenues										22,374	23,464	22,754
Total revenues										108,044	108,617	115,017
Depreciation of rental equipment										32,891	35,256	39,974
Gross profit										50,289	45,797	47,836
Selling and administrative expenses										22,171	21,896	22,930
Income from operations										28,118	23,901	24,906
Interest expense (income) allocation										(2,320)	(2,465)	(2,194)
Income before (benefit) provision for income taxes										26,132	21,315	22,224
Rental equipment acquisitions										58,781	30,505	44,316
Accounts receivable, net (period end)		19,581				19,506				19,581	19,506	21,784
Rental equipment, at cost (period end)		262,325				245,700				262,325	245,700	262,945
Rental equipment, net book value (period end)		109,482				90,172				$ 109,482	$ 90,172	$ 102,191
Utilization (period end)	[1]									61.70%	61.00%	58.70%
Average utilization	[1]									62.90%	60.60%	60.50%
Adler Tanks [Member]
Segment Reporting Information [Line Items]
Rental revenues										$ 64,021	$ 58,585	$ 68,502
Rental related services revenues										24,762	23,807	24,643
Sales and other revenues										2,572	1,438	1,486
Total revenues										91,355	83,830	94,631
Depreciation of rental equipment										15,770	15,940	15,993
Gross profit										43,218	37,409	47,397
Selling and administrative expenses										29,542	27,610	27,494
Income from operations										13,676	9,799	19,903
Interest expense (income) allocation										(3,071)	(3,200)	(2,729)
Income before (benefit) provision for income taxes										10,605	6,599	17,174
Rental equipment acquisitions										4,800	1,030	9,440
Accounts receivable, net (period end)		18,663				16,150				18,663	16,150	17,955
Rental equipment, at cost (period end)		309,808				306,701				309,808	306,701	310,263
Rental equipment, net book value (period end)		208,981				221,778				$ 208,981	$ 221,778	$ 237,927
Utilization (period end)	[1]									57.50%	50.70%	49.70%
Average utilization	[1]									56.00%	50.10%	58.30%
Enviroplex [Member]
Segment Reporting Information [Line Items]
Sales and other revenues	[2]									$ 31,369	$ 22,121	$ 10,612
Total revenues	[2]									31,369	22,121	10,612
Gross profit	[2]									8,903	7,145	2,903
Selling and administrative expenses	[2]									4,309	3,970	3,030
Income from operations	[2]									4,594	3,175	(127)
Interest expense (income) allocation	[2]									440	262	194
Income before (benefit) provision for income taxes	[2]									5,034	3,437	67
Accounts receivable, net (period end)	[2]	$ 8,354				$ 5,305				$ 8,354	$ 5,305	$ 1,728
[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 $31,369, $22,206 and $11,530 in 2017, 2016 and 2015, respectively, which includes inter-segment sales to Mobile Modular of $0, $85 and $918, which have been eliminated in consolidation.

Segment Reporting - Summarize62

Segment Reporting - Summarized Financial Information for Company's Reportable Segments (Parenthetical) (Detail) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Revenues		$ 122,227	$ 135,388	$ 109,582	$ 94,837	$ 105,283	$ 121,993	$ 103,105	$ 93,699	$ 462,034	$ 424,080	$ 404,544
Enviroplex [Member]
Segment Reporting Information [Line Items]
Revenues	[1]									31,369	22,121	10,612
Mobile Modular [Member]
Segment Reporting Information [Line Items]
Revenues										231,266	209,512	184,284
Operating Segments [Member] | Enviroplex [Member]
Segment Reporting Information [Line Items]
Revenues										31,369	22,206	11,530
Inter-segment Eliminations [Member] | Mobile Modular [Member]
Segment Reporting Information [Line Items]
Sales revenues										$ 0	$ 85	$ 918
[1]	Gross Enviroplex sales revenues were $31,369, $22,206 and $11,530 in 2017, 2016 and 2015, respectively, which includes inter-segment sales to Mobile Modular of $0, $85 and $918, which have been eliminated in consolidation.

Quarterly Financial Informati63

Quarterly Financial Information - Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operations Data
Rental revenues	$ 77,705	$ 73,781	$ 69,953	$ 67,978	$ 70,352	$ 67,757	$ 66,747	$ 66,532	$ 289,417	$ 271,388	$ 273,696
Total revenues	122,227	135,388	109,582	94,837	105,283	121,993	103,105	93,699	462,034	424,080	404,544
Gross profit	54,689	58,775	49,211	43,670	49,323	50,433	43,756	40,655	206,345	184,167	176,907
Income from operations	26,786	30,286	21,846	15,822	22,696	24,232	18,073	14,258	94,740	79,259	76,957
Income before (benefit) provision for income taxes	23,949	27,336	18,908	13,259	19,795	21,277	15,006	10,853	83,452	66,931	66,377
Net income	$ 117,724	$ 16,762	$ 11,461	$ 7,973	$ 9,734	$ 12,872	$ 9,079	$ 6,566	$ 153,920	$ 38,251	$ 40,470
Earnings per share:
Basic	$ 4.90	$ 0.70	$ 0.48	$ 0.33	$ 0.41	$ 0.54	$ 0.38	$ 0.28	$ 6.41	$ 1.60	$ 1.60
Diluted	4.82	0.69	0.48	0.33	0.40	0.54	0.38	0.27	6.34	1.60	1.59
Dividends declared per share	$ 0.260	$ 0.260	$ 0.260	$ 0.260	$ 0.255	$ 0.255	$ 0.255	$ 0.255	$ 1.04	$ 1.02	$ 1
Shares used in per share calculations:
Basic	24,044	24,015	23,985	23,950	23,927	23,911	23,900	23,862	23,999	23,900	25,369
Diluted	24,410	24,228	24,092	24,232	24,123	24,041	23,949	23,911	24,269	23,976	25,457
Balance Sheet Data
Rental equipment, net	$ 862,320	$ 865,724	$ 863,207	$ 856,981	$ 856,371	$ 862,528	$ 868,422	$ 867,215	$ 862,320	$ 856,371	$ 869,601
Total assets	1,147,854	1,156,415	1,150,123	1,130,734	1,128,276	1,144,923	1,148,018	1,132,355	1,147,854	1,128,276
Notes payable	303,414	323,117	330,287	323,483	326,266	345,286	363,121	365,772	303,414	326,266
Shareholders’ equity	$ 524,184	$ 412,782	$ 402,365	$ 396,625	$ 394,287	$ 390,600	$ 383,313	$ 380,512	$ 524,184	$ 394,287	$ 379,687	$ 424,531