EMCOR (EME) 10-K 27 Feb 20 2019 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 21, 2020	Jun. 30, 2019
Cover page.
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	1-8267
Entity Registrant Name	EMCOR Group, Inc.
Entity Incorporation, State or Country Code	DE
EIN	11-2125338
Entity Address, Address Line One	301 Merritt Seven
Entity Address, City or Town	Norwalk,
Entity Address, State or Province	CT
Entity Address, Postal Zip Code	06851-1092
City Area Code	(203)
Local Phone Number	849-7800
Title of 12(b) Security	Common Stock
Trading Symbol	EME
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business Flag	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 3,785,000,000
Entity Common Stock, Shares Outstanding		56,259,161
Entity Central Index Key	0000105634
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 358,818	$ 363,907
Accounts receivable, less allowance for doubtful accounts of $14,466 and $15,361, respectively	2,030,813	1,773,620
Contract assets	177,830	158,243
Inventories	40,446	42,321
Prepaid expenses and other	51,976	48,116
Total current assets	2,659,883	2,386,207
Property, plant and equipment, net	156,187	134,351
Operating lease right-of-use assets	245,471	0
Goodwill	1,063,911	990,887
Identifiable intangible assets, net	611,444	488,286
Other assets	93,462	89,076
Total assets	4,830,358	4,088,807
Current liabilities:
Current maturities of long-term debt and finance lease liabilities	18,092	16,013
Accounts payable	665,402	652,091
Contract liabilities	623,642	552,290
Accrued payroll and benefits	382,573	343,069
Other accrued expenses and liabilities	195,757	170,935
Operating lease liabilities, current	53,144	0
Total current liabilities	1,938,610	1,734,398
Borrowings under revolving credit facility	50,000	25,000
Long-term debt and finance lease liabilities	244,139	254,764
Operating lease liabilities, long-term	204,950	0
Other long-term obligations	334,879	333,204
Total liabilities	2,772,578	2,347,366
EMCOR Group, Inc. stockholders’ equity:
Preferred stock, $0.10 par value, 1,000,000 shares authorized, zero issued and outstanding	0	0
Common stock, $0.01 par value, 200,000,000 shares authorized, 60,359,252 and 60,123,184 shares issued, respectively	604	601
Capital surplus	32,274	21,103
Accumulated other comprehensive loss	(89,288)	(87,662)
Retained earnings	2,367,481	2,060,440
Treasury stock, at cost 4,139,421 shares	(253,937)	(253,937)
Total EMCOR Group, Inc. stockholders’ equity	2,057,134	1,740,545
Noncontrolling interests	646	896
Total equity	2,057,780	1,741,441
Total liabilities and equity	$ 4,830,358	$ 4,088,807

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Allowance for doubtful accounts (in US dollars)	$ 14,466	$ 15,361
Preferred stock, par value (in US dollars per share)	$ 0.10	$ 0.10
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in US dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	60,359,252	60,123,184
Treasury stock, shares	4,139,421	4,139,421

Consolidated Statements Of Oper

Consolidated Statements Of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Revenues	$ 9,174,611	$ 8,130,631	$ 7,686,999
Cost of sales	7,818,743	6,925,178	6,539,987
Gross profit	1,355,868	1,205,453	1,147,012
Selling, general and administrative expenses	893,453	799,157	758,714
Restructuring expenses	1,523	2,306	1,577
Impairment loss on goodwill and identifiable intangible assets	0	907	57,819
Operating income	460,892	403,083	328,902
Net periodic pension (cost) income	1,553	2,743	1,652
Interest expense	(13,821)	(13,544)	(12,770)
Interest income	2,265	2,746	965
Income from continuing operations before income taxes	450,889	395,028	318,749
Income tax provision	125,749	109,106	90,699
Income from continuing operations	325,140	285,922	228,050
Loss from discontinued operation, net of income taxes	0	(2,345)	(857)
Net income including noncontrolling interests	325,140	283,577	227,193
Less: Net (income) loss attributable to noncontrolling interests	0	(46)	3
Net income attributable to EMCOR Group, Inc. (in US dollars)	$ 325,140	$ 283,531	$ 227,196
Basic earnings (loss) per common share:
From continuing operations attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	$ 5.78	$ 4.92	$ 3.85
From discontinued operation (in US dollars per share)	0	(0.04)	(0.01)
Net income attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	5.78	4.88	3.84
Diluted earnings (loss) per common share:
From continuing operations attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	5.75	4.89	3.83
From discontinued operation (in US dollars per share)	0	(0.04)	(0.01)
Net income attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	5.75	4.85	3.82
Dividends declared per common share (in US dollars per share)	$ 0.32	$ 0.32	$ 0.32

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income including noncontrolling interests		$ 325,140	$ 283,577	$ 227,193
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments		1,689	(1,322)	(1,384)
Changes in post retirement plans	[1]	(3,315)	7,860	8,887
Other comprehensive (loss) income		(1,626)	6,538	7,503
Comprehensive income		323,514	290,115	234,696
Less: Comprehensive (income) loss attributable to noncontrolling interests		0	(46)	3
Comprehensive income attributable to EMCOR Group, Inc.		$ 323,514	$ 290,069	$ 234,699
[1]	Net of tax benefit (provision) of $0.7 million , $(2.1) million , and $(1.8) million for the years ended December 31, 2019 , 2018 , and 2017 , respectively.

Consolidated Statements Of Co_2

Consolidated Statements Of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Post retirement plans, tax	$ 0.7	$ (2.1)	$ (1.8)

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows - operating activities:
Net income including noncontrolling interests		$ 325,140	$ 283,577	$ 227,193
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization		43,945	38,472	39,915
Amortization of identifiable intangible assets		48,142	42,443	48,594
Provision for doubtful accounts		2,628	2,123	7,264
Deferred income taxes		1,701	4,249	(53,358)
Gain on sale or disposal of property, plant and equipment		(3,981)	(517)	(1,846)
Excess tax benefits from share-based compensation		(984)	(1,646)	(1,616)
Equity loss (income) from unconsolidated entities		2,990	(347)	(864)
Non-cash expense for amortization of debt issuance costs		1,186	1,186	1,186
Non-cash expense from contingent consideration arrangements		1,373	186	317
Non-cash expense for impairment of goodwill and identifiable intangible assets		0	907	57,819
Non-cash share-based compensation expense		11,386	11,030	9,939
Non-cash income from changes in unrecognized tax benefits		0	(72)	(5,641)
Distributions from unconsolidated entities		1,074	3,110	5,506
Changes in operating assets and liabilities, excluding the effect of businesses acquired:
Increase in accounts receivable		(135,954)	(146,101)	(80,514)
Decrease (increase) in inventories		4,345	(3,915)	(4,936)
(Increase) decrease in contract assets		(10,111)	(30,935)	12,433
(Decrease) increase in accounts payable		(33,971)	78,554	54,910
Increase in contract liabilities		51,310	20,726	24,695
Increase (decrease) in accrued payroll and benefits and other accrued expenses and liabilities		49,551	(24,715)	24,017
Changes in other assets and liabilities, net		(4,070)	(7,304)	1,036
Net cash provided by operating activities		355,700	271,011	366,049
Cash flows - investing activities:
Payments for acquisitions of businesses, net of cash acquired		(300,980)	(72,080)	(107,223)
Proceeds from sale or disposal of property, plant and equipment		5,487	1,237	4,014
Purchase of property, plant and equipment		(48,432)	(43,479)	(34,684)
Investments in and advances to unconsolidated entities		(2,252)	(3,484)	(675)
Distributions from unconsolidated entities		838	84	475
Net cash used in investing activities		(345,339)	(117,722)	(138,093)
Cash flows - financing activities:
Proceeds from revolving credit facility		50,000	0	0
Repayments of revolving credit facility		(25,000)	0	(100,000)
Repayments of long-term debt		(15,198)	(15,235)	(15,202)
Repayments of finance lease liabilities		(4,571)	(1,501)	(1,445)
Dividends paid to stockholders		(17,950)	(18,640)	(18,971)
Repurchase of common stock		0	(216,244)	(93,166)
Taxes paid related to net share settlements of equity awards		(6,451)	(3,848)	(3,462)
Issuance of common stock under employee stock purchase plan		6,090	5,765	4,793
Payments for contingent consideration arrangements		(5,917)	(3,339)	(1,017)
Distributions to noncontrolling interests		(250)	0	0
Net cash used in financing activities		(19,247)	(253,042)	(228,470)
Effect of exchange rate changes on cash, cash equivalents and restricted cash		2,592	(3,421)	3,242
(Decrease) increase in cash, cash equivalents and restricted cash		(6,294)	(103,174)	2,728
Cash, cash equivalents and restricted cash at beginning of year (1)	[1]	366,214	469,388	466,660
Cash, cash equivalents and restricted cash at end of period (1)	[1]	$ 359,920	$ 366,214	$ 469,388
[1]	Includes $1.1 million , $2.3 million , $2.0 million and $2.0 million of restricted cash classified as “Prepaid expenses and other” in the Consolidated Balance Sheet as of December 31, 2019, 2018, 2017 and 2016, respectively.

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Cash Flows [Abstract]
Restricted cash	$ 1.1	$ 2.3	$ 2	$ 2

Consolidated Statements Of Equi

Consolidated Statements Of Equity - USD ($) $ in Thousands		Total	Common Stock	Capital Surplus	Accumulated Other Comprehensive (Loss) Income	[1]	Retained Earnings		Treasury Stock	Noncontrolling Interests
Balance at Dec. 31, 2016		$ 1,537,942	$ 606	$ 52,219	$ (101,703)		$ 1,596,269		$ (10,302)	$ 853
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income including noncontrolling interests		227,193					227,196			(3)
Other comprehensive income (loss)		7,503			7,503
Common stock issued under share-based compensation plans		1	2	(1)
Tax withholding for common stock issued under share-based compensation plans		(3,462)		(3,462)
Common stock issued under employee stock purchase plan		4,793	1	4,792
Common stock dividends		(18,971)					(19,135)
Common stock dividends, accrued dividend shares				164
Repurchase of common stock		(90,821)	(10)	(55,646)			(7,774)
Repurchase of common stock	[2]								(27,391)
Share-based compensation expense		9,939		9,939
Balance at Dec. 31, 2017		1,674,117	599	8,005	(94,200)		1,796,556		(37,693)	850
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income including noncontrolling interests		283,577					283,531			46
Other comprehensive income (loss)		6,538			6,538
Cumulative-effect adjustment		(854)					(854)	[3]
Common stock issued under share-based compensation plans		0	1	(1)
Tax withholding for common stock issued under share-based compensation plans		(3,848)		(3,848)
Common stock issued under employee stock purchase plan		5,765	1	5,764
Common stock dividends		(18,640)					(18,793)
Common stock dividends, accrued dividend shares				153
Repurchase of common stock		(216,244)
Repurchase of common stock	[2]								(216,244)
Share-based compensation expense		11,030		11,030
Balance at Dec. 31, 2018		1,741,441	601	21,103	(87,662)		2,060,440		(253,937)	896
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income including noncontrolling interests		325,140					325,140			0
Other comprehensive income (loss)		(1,626)			(1,626)
Common stock issued under share-based compensation plans		0	3	(3)
Tax withholding for common stock issued under share-based compensation plans		(6,451)		(6,451)
Common stock issued under employee stock purchase plan		6,090		6,090
Common stock dividends		(17,950)					(18,099)
Common stock dividends, accrued dividend shares				149
Distributions to noncontrolling interests		(250)								(250)
Share-based compensation expense		11,386		11,386
Balance at Dec. 31, 2019		$ 2,057,780	$ 604	$ 32,274	$ (89,288)		$ 2,367,481		$ (253,937)	$ 646
[1]	Represents cumulative foreign currency translation and post retirement liability adjustments of $0.8 million and $(90.1) million , respectively, as of December 31, 2019, $(0.9) million and $(86.8) million , respectively, as of December 31, 2018, and $0.5 million and $(94.7) million , respectively, as of December 31, 2017.
[2]	Beginning June 1, 2017, shares of common stock repurchased are held as treasury stock by the Company.
[3]	Represents adjustment to retained earnings upon the adoption of Accounting Standards Codification Topic 606.

Consolidated Statements Of Eq_2

Consolidated Statements Of Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2017
Cumulative foreign currency translation	$ (900)	$ 800	$ 500
Post retirement liability adjustments	(86,800)	$ (90,100)	$ (94,700)
Cumulative effect on retained earnings, net of tax	$ 854

Nature of Operations

Nature of Operations	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations	NATURE OF OPERATIONS References to the “Company,” “EMCOR,” “we,” “us,” “our” and similar words refer to EMCOR Group, Inc. and its consolidated subsidiaries unless the context indicates otherwise.

Summary of Significant Accounti

Summary of Significant Accounting Policies (Notes)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Principles of Consolidation The consolidated financial statements include the accounts of the Company and its majority-owned subsidiaries and joint ventures. Significant intercompany accounts and transactions have been eliminated. All investments over which we exercise significant influence, but do not control (a 20% to 50% ownership interest), are accounted for using the equity method of accounting. For joint ventures that have been accounted for using the consolidation method of accounting, noncontrolling interests represent the allocation of earnings to our joint venture partners who either have a minority-ownership interest in the joint venture or are not at risk for the majority of losses of the joint venture. The results of operations of companies acquired have been included in the results of operations from the date of the respective acquisition. Principles of Preparation The preparation of the consolidated financial statements, in conformity with accounting principles generally accepted in the United States, requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could materially differ from those estimates. Our reportable segments reflect certain reclassifications of prior year amounts from our United States mechanical construction and facilities services segment to our United States building services and our United States industrial services segments due to changes in our internal reporting structure. During the third quarter of 2014, we ceased construction operations in the United Kingdom. The results of the construction operations of our United Kingdom segment for all periods are presented as discontinued operations. Revenue Recognition The Company adopted Accounting Standards Codification Topic 606, “Revenue from Contracts with Customers” (“ASC 606”) on January 1, 2018. In accordance with ASC 606, revenue is recognized when promised goods or services are transferred to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those goods or services. Refer to Note 3 - Revenue from Contracts with Customers of the notes to consolidated financial statements for additional information. For the periods presented prior to the adoption of ASC 606, revenues from long-term construction contracts were recognized in accordance with ASC Topic 605-35, “Revenue Recognition-Construction-Type and Production-Type Contracts.” Revenues from the performance of services for maintenance, repair and retrofit work were recognized consistent with the performance of the services, generally on a pro-rata basis over the life of the contractual arrangement. Revenues related to the engineering, manufacturing and repairing of shell and tube heat exchangers were recognized when the product was shipped and all other revenue recognition criteria were met. Cash and cash equivalents For purposes of the consolidated financial statements, we consider all highly liquid instruments with original maturities of three months or less to be cash equivalents. We maintain a centralized cash management system whereby our excess cash balances are invested in high quality, short-term money market instruments, which are considered cash equivalents. We have cash balances in certain of our domestic bank accounts that exceed federally insured limits. Allowance for Doubtful Accounts Accounts receivable are recorded at the invoiced amount and do not bear interest. The Company maintains an allowance for doubtful accounts. This allowance is based upon the best estimate of the probable losses in existing accounts receivable. The Company determines the allowances based upon individual accounts when information indicates the customers may have an inability to meet their financial obligations, as well as historical collection and write-off experience. These amounts are re-evaluated and adjusted on a regular basis as additional information is received. Actual write-offs are charged against the allowance when collection efforts have been unsuccessful. At December 31, 2019 and 2018 , our accounts receivable of $2,030.8 million and $1,773.6 million , respectively, were recorded net of allowances for doubtful accounts of $14.5 million and $15.4 million , respectively. The provision for doubtful accounts during 2019 , 2018 , and 2017 amounted to approximately $2.6 million , $2.1 million , and $7.3 million , respectively. Inventories Inventories are stated at the lower of cost or net realizable value. Cost is determined principally using the average cost method. Property, plant and equipment Property, plant and equipment is stated at cost. Depreciation, including amortization of assets under finance leases, is recorded principally using the straight-line method over estimated useful lives of 3 to 10 years for machinery and equipment, 3 to 7 years for vehicles, furniture and fixtures and computer hardware/software, and 25 years for buildings. Leasehold improvements are amortized over the shorter of the remaining life of the lease term or the expected useful life of the improvement. The carrying values of property, plant and equipment are reviewed for impairment whenever facts and circumstances indicate that the carrying amount may not be fully recoverable. In performing this review for recoverability, property, plant and equipment is assessed for possible impairment by comparing their carrying values to their undiscounted net pre-tax cash flows expected to result from the use of the asset. Impaired assets are written down to their fair values, generally determined based on their estimated future discounted cash flows. Based on the results of our testing for the years ended December 31, 2019 , 2018 , and 2017 , no impairment of property, plant and equipment was recognized. Goodwill and Identifiable Intangible Assets Goodwill and other identifiable intangible assets with indefinite lives that are not being amortized, such as trade names, are tested at least annually for impairment (which we test each October 1, absent any earlier identified impairment indicators) and are written down if impaired. Identifiable intangible assets with finite lives are amortized over their useful lives and are reviewed for impairment whenever facts and circumstances indicate that their carrying values may not be fully recoverable. See Note 9 - Goodwill and Identifiable Intangible Assets of the notes to consolidated financial statements for additional information. Insurance Liabilities Insurance liabilities for automobile liability, workers’ compensation and general liability claims are determined actuarially based on claims filed and an estimate of claims incurred but not yet reported. At December 31, 2019 and 2018 , the estimated current portion of such undiscounted insurance liabilities of $48.3 million and $44.6 million , respectively, were included in “Other accrued expenses and liabilities” in the accompanying Consolidated Balance Sheets. The estimated non-current portion of such undiscounted insurance liabilities included in “Other long-term obligations” at December 31, 2019 and 2018 were $186.0 million and $179.1 million , respectively. The current portion of anticipated insurance recoveries of $13.8 million and $12.6 million at December 31, 2019 and 2018 , respectively, were included in “Prepaid expenses and other” and the non-current portion of anticipated insurance recoveries of $50.9 million and $49.3 million at December 31, 2019 and 2018 , respectively, were included in “Other assets” in the accompanying Consolidated Balance Sheets. Foreign Operations The financial statements and transactions of our foreign subsidiaries are maintained in their functional currency and translated into U.S. dollars in accordance with Accounting Standards Codification Topic 830, “Foreign Currency Matters.” Translation adjustments have been recorded as “Accumulated other comprehensive loss,” a separate component of “Equity.” Income Taxes We account for income taxes in accordance with the provisions of Accounting Standards Codification Topic 740, “Income Taxes” (“ASC 740”). ASC 740 requires an asset and liability approach which requires the recognition of deferred income tax assets and deferred income tax liabilities for the expected future tax consequences of temporary differences between the carrying amounts and the tax bases of assets and liabilities. Valuation allowances are established when necessary to reduce deferred income tax assets when it is more likely than not that a tax benefit will not be realized. We account for uncertain tax positions in accordance with the provisions of ASC 740. We recognize accruals of interest related to unrecognized tax benefits as a component of the income tax provision. Valuation of Share-Based Compensation Plans We have various types of share-based compensation plans and programs, which are administered by our Board of Directors or its Compensation and Personnel Committee. See Note 14 - Share-Based Compensation Plans of the notes to consolidated financial statements for additional information regarding the share-based compensation plans and programs. We account for share-based payments in accordance with the provisions of Accounting Standards Codification Topic 718, “Compensation-Stock Compensation” (“ASC 718”). ASC 718 requires that all share-based payments issued to acquire goods or services, including grants of employee stock options, be recognized in the statement of operations based on their fair values. Compensation expense related to share-based awards is recognized over the requisite service period, which is generally the vesting period. For shares subject to graded vesting, our policy is to apply the straight-line method in recognizing compensation expense. ASC 718 requires the benefits of tax deductions in excess of recognized compensation expense to be recognized in the Consolidated Statements of Operations when the underlying awards vest or are settled. New Accounting Pronouncements On January 1, 2019, we adopted the accounting pronouncement issued by the Financial Accounting Standards Board (“FASB”) to replace existing lease accounting guidance. This pronouncement is intended to provide enhanced transparency and comparability by requiring lessees to record right-of-use assets and corresponding lease liabilities on the balance sheet for most leases. Expenses associated with leases continue to be recognized in a manner similar to previous accounting guidance. We adopted this pronouncement utilizing the transition practical expedient added by the FASB, which eliminated the requirement that entities apply the new lease standard to the comparative periods presented in the year of adoption. The adoption of this accounting pronouncement resulted in the recognition of operating lease right-of-use assets and associated lease liabilities on our balance sheet of $220.2 million and $227.1 million , respectively, as of January 1, 2019. Additional required disclosures have been included within Note 17 - Leases of the notes to consolidated financial statements. Such adoption did not have an impact on our liquidity, results of operations or our compliance with the various covenants contained within our 2016 Credit Agreement as described in further detail within Note 10 - Debt of the notes to consolidated financial statements. On January 1, 2019, we adopted the accounting pronouncement issued by the FASB related to the reporting of certain items in accumulated other comprehensive income (loss) (“AOCI”). This guidance provides entities the option to reclassify to retained earnings certain tax effects stranded in AOCI as a result of tax reform. As part of our adoption of this accounting pronouncement, we elected not to reclassify the stranded tax effects related to the retirement plans of our United States subsidiaries as such amounts are immaterial. Tax effects remaining in AOCI will be released upon liquidation of each individual retirement plan. In June 2016, an accounting pronouncement was issued by the FASB which changes the way in which entities estimate and present credit losses for most financial assets, including accounts receivable. This pronouncement is effective for annual and interim periods beginning after December 15, 2019, with early adoption permitted. In preparation for adoption, we have substantially completed a process to identify and group financial assets with similar characteristics into collective pools. We have additionally begun implementing processes and internal controls to identify information, including macroeconomic forecasts and key credit indicators, relevant to estimating expected credit losses. As a result of the procedures performed to date, we do not anticipate that the adoption of this pronouncement will have a material impact on our financial position and/or results of operations.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	REVENUE FROM CONTRACTS WITH CUSTOMERS The Company recognizes revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those goods or services by applying the following five step model: (1) Identify the contract with a customer A contract with a customer exists when: (a) the parties have approved the contract and are committed to perform their respective obligations, (b) the rights of the parties can be identified, (c) payment terms can be identified, (d) the arrangement has commercial substance, and (e) collectibility of consideration is probable. Judgment is required when determining if the contractual criteria are met, specifically in the earlier stages of a project when a formally executed contract may not yet exist. In these situations, the Company evaluates all relevant facts and circumstances, including the existence of other forms of documentation or historical experience with our customers that may indicate a contractual agreement is in place and revenue should be recognized. In determining if the collectibility of consideration is probable, the Company considers the customer’s ability and intention to pay such consideration through an evaluation of several factors, including an assessment of the creditworthiness of the customer and our prior collection history with such customer. (2) Identify the performance obligations in the contract At contract inception, the Company assesses the goods or services promised in a contract and identifies, as a separate performance obligation, each distinct promise to transfer goods or services to the customer. The identified performance obligations represent the “unit of account” for purposes of determining revenue recognition. In order to properly identify separate performance obligations, the Company applies judgment in determining whether each good or service provided is: (a) capable of being distinct, whereby the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer, and (b) distinct within the context of the contract, whereby the transfer of the good or service to the customer is separately identifiable from other promises in the contract. In addition, when assessing performance obligations within a contract, the Company considers the warranty provisions included within such contract. To the extent the warranty terms provide the customer with an additional service, other than assurance that the promised good or service complies with agreed upon specifications, such warranty is accounted for as a separate performance obligation. In determining whether a warranty provides an additional service, the Company considers each warranty provision in comparison to warranty terms which are standard in the industry. Our contracts are often modified through change orders to account for changes in the scope and price of the goods or services we are providing. Although the Company evaluates each change order to determine whether such modification creates a separate performance obligation, the majority of our change orders are for goods or services that are not distinct within the context of our original contract, and therefore, are not treated as separate performance obligations. (3) Determine the transaction price The transaction price represents the amount of consideration to which the Company expects to be entitled in exchange for transferring promised goods or services to our customers. The consideration promised within a contract may include fixed amounts, variable amounts, or both. To the extent the performance obligation includes variable consideration, including contract bonuses and penalties that can either increase or decrease the transaction price, the Company estimates the amount of variable consideration to be included in the transaction price utilizing one of two prescribed methods, depending on which method better predicts the amount of consideration to which the entity will be entitled. Such methods include: (a) the expected value method, whereby the amount of variable consideration to be recognized represents the sum of probability weighted amounts in a range of possible consideration amounts, and (b) the most likely amount method, whereby the amount of variable consideration to be recognized represents the single most likely amount in a range of possible consideration amounts. When applying these methods, the Company considers all information that is reasonably available, including historical, current, and estimates of future performance. The expected value method is typically utilized in situations where a contract contains a large number of possible outcomes while the most likely amount method is typically utilized in situations where a contract has only two possible outcomes. Variable consideration is included in the transaction price only to the extent it is probable, in the Company’s judgment, that a significant future reversal in the amount of cumulative revenue recognized under the contract will not occur when the uncertainty associated with the variable consideration is subsequently resolved. This threshold is referred to as the variable consideration constraint. In assessing whether to apply the variable consideration constraint, the Company considers if factors exist that could increase the likelihood or the magnitude of a potential reversal of revenue, including, but not limited to, whether: (a) the amount of consideration is highly susceptible to factors outside of the Company’s influence, such as the actions of third parties, (b) the uncertainty surrounding the amount of consideration is not expected to be resolved for a long period of time, (c) the Company’s experience with similar types of contracts is limited or that experience has limited predictive value, (d) the Company has a practice of either offering a broad range of price concessions or changing the payment terms and conditions of similar contracts in similar circumstances, and (e) the contract has a large number and broad range of possible consideration amounts. Pending change orders represent one of the most common forms of variable consideration included within contract value and typically represent contract modifications for which a change in scope has been authorized or acknowledged by our customer, but the final adjustment to contract price is yet to be negotiated. In estimating the transaction price for pending change orders, the Company considers all relevant facts, including documented correspondence with the customer regarding acknowledgment of and/or agreement with the modification, as well as historical experience with the customer or similar contractual circumstances. Based upon this assessment, the Company estimates the transaction price, including whether the variable consideration constraint should be applied. Contract claims are another form of variable consideration which is common within our industry. Claim amounts represent revenue that has been recognized for contract modifications that are not submitted or are in dispute as to both scope and price. In estimating the transaction price for claims, the Company considers all relevant facts available. However, given the uncertainty surrounding claims, including the potential long-term nature of dispute resolution and the broad range of possible consideration amounts, there is an increased likelihood that any additional contract revenue associated with contract claims is constrained. The resolution of claims involves negotiations and, in certain cases, litigation. In the event litigation costs are incurred by us in connection with claims, such litigation costs are expensed as incurred, although we may seek to recover these costs. For some transactions, the receipt of consideration does not match the timing of the transfer of goods or services to the customer. For such contracts, the Company evaluates whether this timing difference represents a financing arrangement within the contract. Although rare, if a contract is determined to contain a significant financing component, the Company adjusts the promised amount of consideration for the effects of the time value of money when determining the transaction price of such contract. Although our customers may retain a portion of the contract price until completion of the project and final contract settlement, these retainage amounts are not considered a significant financing component as the intent of the withheld amounts is to provide the customer with assurance that we will complete our obligations under the contract rather than to provide financing to the customer. In addition, although we may be entitled to advanced payments from our customers on certain contracts, these advanced payments generally do not represent a significant financing component as the payments are used to meet working capital demands that can be higher in the early stages of a contract, as well as to protect us from our customer failing to meet its obligations under the contract. Changes in the estimates of transaction prices are recognized on a cumulative catch-up basis in the period in which the revisions to the estimates are made. Such changes in estimates can result in the recognition of revenue in a current period for performance obligations which were satisfied or partially satisfied in prior periods. Such changes in estimates may also result in the reversal of previously recognized revenue if the ultimate outcome differs from the Company’s previous estimate. There were no significant amounts of revenue recognized during the year ended December 31, 2019 related to performance obligations satisfied in prior periods. For the year ended December 31, 2018 , we recognized revenue of $7.3 million associated with the final settlement of contract value for three projects which were completed in prior periods. For the years ended December 31, 2019 and 2018 , there were no significant reversals of revenue recognized associated with the revision of transaction prices. (4) Allocate the transaction price to performance obligations in the contract For contracts that contain multiple performance obligations, the Company allocates the transaction price to each performance obligation based on a relative standalone selling price. The Company determines the standalone selling price based on the price at which the performance obligation would have been sold separately in similar circumstances to similar customers. If the standalone selling price is not observable, the Company estimates the standalone selling price taking into account all available information such as market conditions and internal pricing guidelines. In certain circumstances, the standalone selling price is determined using an expected profit margin on anticipated costs related to the performance obligation. (5) Recognize revenue as performance obligations are satisfied The Company recognizes revenue at the time the related performance obligation is satisfied by transferring a promised good or service to its customers. A good or service is considered to be transferred when the customer obtains control. The Company can transfer control of a good or service and satisfy its performance obligations either over time or at a point in time. The Company transfers control of a good or service over time and, therefore, satisfies a performance obligation and recognizes revenue over time if one of the following three criteria are met: (a) the customer simultaneously receives and consumes the benefits provided by the Company’s performance as we perform, (b) the Company’s performance creates or enhances an asset that the customer controls as the asset is created or enhanced, or (c) the Company’s performance does not create an asset with an alternative use to us, and we have an enforceable right to payment for performance completed to date. For our performance obligations satisfied over time, we recognize revenue by measuring the progress toward complete satisfaction of that performance obligation. The selection of the method to measure progress towards completion can be either an input method or an output method and requires judgment based on the nature of the goods or services to be provided. For our construction contracts, revenue is generally recognized over time as our performance creates or enhances an asset that the customer controls as it is created or enhanced. Our fixed price construction projects generally use a cost-to-cost input method to measure our progress towards complete satisfaction of the performance obligation as we believe it best depicts the transfer of control to the customer which occurs as we incur costs on our contracts. Under the cost-to-cost measure of progress, the extent of progress towards completion is measured based on the ratio of costs incurred to date to the total estimated costs at completion of the performance obligation. For our unit price construction contracts, progress towards complete satisfaction is measured through an output method, such as the amount of units produced or delivered, when our performance does not produce significant amounts of work in process or finished goods prior to complete satisfaction of such performance obligations. For our services contracts, revenue is also generally recognized over time as the customer simultaneously receives and consumes the benefits of our performance as we perform the service. For our fixed price service contracts with specified service periods, revenue is generally recognized on a straight-line basis over such service period when our inputs are expended evenly, and the customer receives and consumes the benefits of our performance throughout the contract term. The timing of revenue recognition for the manufacturing of new build heat exchangers within our United States industrial services segment depends on the payment terms of the contract, as our performance does not create an asset with an alternative use to us. For those contracts for which we have a right to payment for performance completed to date at all times throughout our performance, inclusive of a cancellation, we recognize revenue over time. For these performance obligations, we use a cost-to-cost input method to measure our progress towards complete satisfaction of the performance obligation as we believe it best depicts the transfer of control to the customer which occurs as we incur costs on our contracts. However, for those contracts for which we do not have a right, at all times, to payment for performance completed to date, we recognize revenue at the point in time when control is transferred to the customer. For bill-and-hold arrangements, revenue is recognized when the customer obtains control of the heat exchanger, which may be prior to shipping, if certain recognition criteria are met. For certain of our revenue streams, such as call-out repair and service work, outage services, refinery turnarounds, and specialty welding services that are performed under time and materials contracts, our progress towards complete satisfaction of such performance obligations is measured using an output method as the customer receives and consumes the benefits of our performance completed to date. Due to uncertainties inherent in the estimation process, it is possible that estimates of costs to complete a performance obligation will be revised in the near-term. For those performance obligations for which revenue is recognized using a cost-to-cost input method, changes in total estimated costs, and related progress towards complete satisfaction of the performance obligation, are recognized on a cumulative catch-up basis in the period in which the revisions to the estimates are made. When the current estimate of total costs for a performance obligation indicate a loss, a provision for the entire estimated loss on the unsatisfied performance obligation is made in the period in which the loss becomes evident. During 2019, there were no changes in total estimated costs that had a significant impact on our operating results. During 2018, we recognized losses of $10.0 million related to a change in total estimated costs on a transportation project within our United States electrical construction and facilities services segment, resulting in part from contract scope issues. There were no other changes in total estimated costs that resulted in a significant impact to our operating results for the year ended December 31, 2018. Disaggregation of Revenues Our revenues are principally derived from contracts to provide construction services relating to electrical and mechanical systems, as well as to provide a number of building services and industrial services to our customers. Our contracts are with many different customers in numerous industries. Refer to Note 19 - Segment Information of the notes to the consolidated financial statements for additional information on how we disaggregate our revenues by reportable segment, as well as a more complete description of our business. The following tables provide further disaggregation of our revenues by categories we use to evaluate our financial performance within each of our reportable segments (in thousands): 2019 % of Total 2018 % of United States electrical construction and facilities services: Commercial market sector $ 1,081,737 49 % $ 839,045 43 % Institutional market sector 125,537 6 % 110,046 6 % Hospitality market sector 16,985 1 % 32,338 2 % Manufacturing market sector 462,953 21 % 388,157 20 % Healthcare market sector 88,752 4 % 126,218 6 % Transportation market sector 210,515 9 % 284,464 14 % Water and wastewater market sector 19,921 1 % 23,337 1 % Short duration projects (1) 158,619 7 % 120,109 6 % Service work 54,955 2 % 34,105 2 % 2,219,974 1,957,819 Less intersegment revenues (3,374 ) (3,496 ) Total segment revenues $ 2,216,600 $ 1,954,323 2019 % of 2018 % of United States mechanical construction and facilities services: Commercial market sector $ 1,185,129 36 % $ 1,057,542 35 % Institutional market sector 313,409 9 % 289,882 10 % Hospitality market sector 35,385 1 % 93,827 3 % Manufacturing market sector 533,699 16 % 393,637 13 % Healthcare market sector 304,622 9 % 240,818 8 % Transportation market sector 32,686 1 % 19,415 1 % Water and wastewater market sector 202,428 6 % 176,546 6 % Short duration projects (1) 365,721 11 % 318,413 11 % Service work 378,839 11 % 385,671 13 % 3,351,918 2,975,751 Less intersegment revenues (11,581 ) (12,908 ) Total segment revenues $ 3,340,337 $ 2,962,843 ________ (1) Represents those projects which generally are completed within three months or less. 2019 % of 2018 % of United States building services: Commercial site-based services $ 571,345 27 % $ 519,641 28 % Government site-based services 176,282 8 % 213,677 11 % Mechanical services 1,238,420 59 % 1,032,082 55 % Energy services 120,825 6 % 110,085 6 % Total segment revenues $ 2,106,872 $ 1,875,485 2019 % of 2018 % of United States industrial services: Field services $ 922,308 85 % $ 752,458 82 % Shop services 165,235 15 % 170,651 18 % Total segment revenues 1,087,543 923,109 Total United States operations $ 8,751,352 $ 7,715,760 2019 % of 2018 % of United Kingdom building services: Service work $ 212,876 50 % $ 216,880 52 % Projects & extras 210,383 50 % 197,991 48 % Total segment revenues $ 423,259 $ 414,871 Total worldwide operations $ 9,174,611 $ 8,130,631 Contract Assets and Contract Liabilities Accounts receivable are recognized in the period when our right to consideration is unconditional. Accounts receivable are recognized net of an allowance for doubtful accounts. A considerable amount of judgment is required in assessing the likelihood of realization of receivables. The timing of revenue recognition may differ from the timing of invoicing to customers. Contract assets include unbilled amounts from our long-term construction projects when revenues recognized under the cost-to-cost measure of progress exceed the amounts invoiced to our customers, as the amounts cannot be billed under the terms of our contracts. Such amounts are recoverable from our customers based upon various measures of performance, including achievement of certain milestones, completion of specified units or completion of a contract. In addition, many of our time and materials arrangements, as well as our contracts to perform turnaround services within the United States industrial services segment, are billed in arrears pursuant to contract terms that are standard within the industry, resulting in contract assets and/or unbilled receivables being recorded, as revenue is recognized in advance of billings. Also included in contract assets are amounts we seek or will seek to collect from customers or others for errors or changes in contract specifications or design, contract change orders or modifications in dispute or unapproved as to scope and/or price, or other customer-related causes of unanticipated additional contract costs (claims and unapproved change orders). Our contract assets do not include capitalized costs to obtain and fulfill a contract. Contract assets are generally classified as current within the Consolidated Balance Sheets. As of December 31, 2019 and 2018 , contract assets included unbilled revenues for unapproved change orders of approximately $33.1 million and $25.2 million , respectively. As of December 31, 2019 and 2018 , there were no claim amounts included within contract assets or accounts receivable. There were contractually billed amounts and retention related to contracts with unapproved change orders and claims of approximately $89.0 million and $96.1 million as of December 31, 2019 and 2018 , respectively. For contracts in claim status, contractually billed amounts will generally not be paid by the customer to us until final resolution of the related claims. Contract liabilities from our long-term construction contracts arise when amounts invoiced to our customers exceed revenues recognized under the cost-to-cost measure of progress. Contract liabilities additionally include advanced payments from our customers on certain contracts. Contract liabilities decrease as we recognize revenue from the satisfaction of the related performance obligation and are recorded as either current or long-term, depending upon when we expect to recognize such revenue. The long-term portion of contract liabilities is included in “Other long-term obligations” in the Consolidated Balance Sheets. Net contract liabilities consisted of the following (in thousands): 2019 2018 Contract assets, current $ 177,830 $ 158,243 Contract assets, non-current — — Contract liabilities, current (623,642 ) (552,290 ) Contract liabilities, non-current (2,142 ) (2,069 ) Net contract liabilities $ (447,954 ) $ (396,116 ) Included within net contract liabilities were $406.6 million and $359.2 million of net contract liabilities on uncompleted construction projects as of December 31, 2019 and 2018, respectively, as follows (in thousands): 2019 2018 Costs incurred on uncompleted construction contracts $ 9,885,192 $ 8,656,642 Estimated earnings, thereon 1,349,338 1,172,224 11,234,530 9,828,866 Less: billings to date 11,641,082 10,188,023 $ (406,552 ) $ (359,157 ) The $51.8 million increase in net contract liabilities for the year ended December 31, 2019 was primarily attributable to the $47.4 million increase in the net contract liabilities on our uncompleted long-term construction contracts, partially as a result of the timing of billings to our customers as amounts invoiced exceeded the revenue recognized on certain large projects in the earlier stages of completion. Contract assets and contract liabilities increased by approximately $8.2 million and $29.0 million , respectively, as a result of acquisitions made in 2019 . There was no significant impairment of contract assets recognized during the period. Contract Retentions As of December 31, 2019 and 2018 , accounts receivable included $298.5 million and $254.6 million , respectively, of retainage billed under terms of our contracts. These retainage amounts represent amounts which have been contractually invoiced to customers where payments have been partially withheld pending the achievement of certain milestones, satisfaction of other contractual conditions or completion of the project. We estimate that approximately 88% of this retainage will be collected during 2020 . As of December 31, 2019 and 2018 , accounts payable included $64.7 million and $43.3 million , respectively, of retainage withheld under terms of our subcontracts. These retainage amounts represent amounts invoiced to the Company by our subcontractors where payments have been partially withheld pending the achievement of certain milestones, satisfaction of other contractual conditions or upon completion of the project. We estimate that approximately 86% of this retainage will be paid during 2020 . Transaction Price Allocated to Remaining Unsatisfied Performance Obligations The following table presents the transaction price allocated to remaining unsatisfied performance obligations (“remaining performance obligations”) for each of our reportable segments and their respective percentages of total remaining performance obligations (in thousands, except for percentages): 2019 % of Total Remaining performance obligations: United States electrical construction and facilities services $ 1,036,216 26 % United States mechanical construction and facilities services 2,229,090 55 % United States building services 542,269 13 % United States industrial services 104,613 3 % Total United States operations 3,912,188 97 % United Kingdom building services 124,176 3 % Total worldwide operations $ 4,036,364 100 % Our remaining performance obligations at December 31, 2019 were $4.04 billion . Remaining performance obligations increase with awards of new contracts and decrease as we perform work and recognize revenue on existing contracts. We include a project within our remaining performance obligations at such time the project is awarded and agreement on contract terms has been reached. Our remaining performance obligations include amounts related to contracts for which a fixed price contract value is not assigned when a reasonable estimate of total transaction price can be made. Remaining performance obligations include unrecognized revenues to be realized from uncompleted construction contracts. Although many of our construction contracts are subject to cancellation at the election of our customers, in accordance with industry practice, we do not limit the amount of unrecognized revenue included within remaining performance obligations for these contracts due to the inherent substantial economic penalty that would be incurred by our customers upon cancellation. We believe our reported remaining performance obligations for our construction contracts are firm and contract cancellations have not had a material adverse effect on us. Remaining performance obligations also include unrecognized revenues expected to be realized over the remaining term of service contracts. However, to the extent a service contract includes a cancellation clause which allows for the termination of such contract by either party without a substantive penalty, the remaining contract term, and therefore, the amount of unrecognized revenues included within remaining performance obligations, is limited to the notice period required for the termination. Our remaining performance obligations are comprised of: (a) original contract amounts, (b) change orders for which we have received written confirmations from our customers, (c) pending change orders for which we expect to receive confirmations in the ordinary course of business, (d) claim amounts that we have made against customers for which we have determined we have a legal basis under existing contractual arrangements and as to which the variable consideration constraint does not apply, and (e) other forms of variable consideration to the extent that such variable consideration has been included within the transaction price of our contracts. Such claim and other variable consideration amounts were immaterial for all periods presented. Refer to the table below for additional information regarding our remaining performance obligations, including an estimate of when we expect to recognize such remaining performance obligations as revenue (in thousands): Within one year Greater than one year Remaining performance obligations: United States electrical construction and facilities services $ 861,268 $ 174,948 United States mechanical construction and facilities services 1,802,865 426,225 United States building services 532,540 9,729 United States industrial services 104,613 — Total United States operations 3,301,286 610,902 United Kingdom building services 83,558 40,618 Total worldwide operations $ 3,384,844 $ 651,520

Acquisitions Of Businesses

Acquisitions Of Businesses	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Acquisitions Of Businesses	ACQUISITIONS OF BUSINESSES Acquisitions are accounted for utilizing the acquisition method of accounting and the prices paid for them are allocated to their respective assets and liabilities based upon the estimated fair value of such assets and liabilities at the dates of their respective acquisition by us. On November 1, 2019 , we completed the acquisition of Batchelor & Kimball, Inc. (“BKI”), a leading full service provider of mechanical construction and maintenance services. This acquisition strengthens our position and broadens our capabilities in the Southern and Southeastern regions of the United States, and its results of operations have been included within our United States mechanical construction and facilities services segment. Under the terms of the transaction, we acquired 100% of BKI’s outstanding capital stock for total consideration of approximately $220.0 million . In connection with the acquisition of BKI, we acquired working capital of $29.8 million and other net assets of $4.9 million and have preliminarily ascribed $43.6 million to goodwill and $141.7 million to identifiable intangible assets. Goodwill is calculated as the excess of the consideration transferred over the fair value of the net assets acquired and represents the future economic benefits expected from this strategic acquisition. The weighted average amortization period for the identifiable intangible assets, which consist of a trade name, customer relationships, and contract backlog, is approximately 10.5 years. In addition to BKI, during 2019, we completed six other acquisitions for total consideration of $85.3 million . Such companies include: (a) a company which provides electrical contracting services in central Iowa, the results of operations of which have been included within our United States electrical construction and facilities services segment, (b) a company which provides mechanical contracting services in south-central and eastern Texas, the results of operations of which have been included within our United States mechanical construction and facilities services segment, and (c) four companies within our United States building services segment which bolster our presence in geographies where we have existing operations and provide either mobile mechanical services or building automation and controls solutions. In connection with these acquisitions, we acquired working capital of $25.3 million and other net assets of $1.3 million and have preliminarily ascribed $29.1 million to goodwill and $29.6 million to identifiable intangible assets. During 2018, we acquired four companies for total consideration of $71.6 million . Two companies provide mobile mechanical services, one within the Eastern region and the other within the Western region of the United States. The third company is a full service provider of mechanical services within the Southern region of the United States. The results of these three companies have been included in our United States building services segment. The fourth company provides electrical construction and maintenance services for industrial and commercial buildings in north Texas, and its results have been included in our United States electrical construction and facilities services segment. In connection with these acquisitions, we acquired working capital of $8.7 million and have ascribed $26.3 million to goodwill and $36.6 million to identifiable intangible assets. During 2017, we acquired three companies for total consideration of $111.9 million . One company provides fire protection and alarm services primarily in the Southern region of the United States. The second company provides millwright services for manufacturing companies throughout the United States. Both of their results have been included in our United States mechanical construction and facilities services segment. The third company provides mobile mechanical services within the Western region of the United States, and its results have been included in our United States building services segment. In connection with these acquisitions, we acquired working capital of $12.3 million and other net assets of $2.3 million and have ascribed $40.7 million to goodwill and $56.6 million to identifiable intangible assets. We expect that all of the goodwill acquired in connection with these acquisitions will be deductible for tax purposes. The purchase price allocations for the businesses acquired in 2019 are preliminary and subject to change during their respective measurement periods. The purchase price allocations for the businesses acquired in 2018 and 2017 have been finalized during their respective measurement periods with an insignificant impact.

Disposition Of Assets

Disposition Of Assets	12 Months Ended
	Dec. 31, 2019
Discontinued Operations and Disposal Groups [Abstract]
Disposition Of Assets	DISPOSITION OF ASSETS Due to a historical pattern of losses in the construction operations of our United Kingdom segment and our negative assessment of construction market conditions in the United Kingdom, we ceased construction operations in the United Kingdom during the third quarter of 2014. The results of the construction operations of our United Kingdom segment for all periods are presented in the Consolidated Financial Statements as discontinued operations. No income or expense was recognized from discontinued operations for the year ended December 31, 2019. The results of discontinued operations for the years ended December 31, 2018 and 2017 were as follows (in thousands): 2018 2017 Revenues $ — $ 863 Loss from discontinued operation, net of income taxes $ (2,345 ) $ (857 ) Diluted loss per share from discontinued operation $ (0.04 ) $ (0.01 ) The loss from discontinued operations in 2018 was primarily due to the settlement of a previously outstanding legal matter. The loss from discontinued operations in 2017 was primarily due to legal costs incurred, partially offset by revenues recognized upon the settlement of a previously outstanding contract claim. Included in the Consolidated Balance Sheet at December 31, 2018 were approximately $3.7 million of current liabilities associated with the discontinued operation, primarily consisting of contract retentions, contract warranty obligations and other accrued expenses. No significant liabilities remain as of December 31, 2019 .

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE The following tables summarize our calculation of Basic and Diluted Earnings (Loss) per Common Share (“EPS”) for the years ended December 31, 2019 , 2018 , and 2017 (in thousands, except share and per share data): 2019 2018 2017 Numerator: Income from continuing operations attributable to EMCOR Group, Inc. common stockholders $ 325,140 $ 285,876 $ 228,053 Loss from discontinued operation, net of income taxes — (2,345 ) (857 ) Net income attributable to EMCOR Group, Inc. common stockholders $ 325,140 $ 283,531 $ 227,196 Denominator: Weighted average shares outstanding used to compute basic earnings (loss) per common share 56,208,280 58,112,838 59,254,256 Effect of dilutive securities—Share-based awards 311,001 330,629 364,713 Shares used to compute diluted earnings (loss) per common share 56,519,281 58,443,467 59,618,969 Basic earnings (loss) per common share: From continuing operations attributable to EMCOR Group, Inc. common stockholders $ 5.78 $ 4.92 $ 3.85 From discontinued operation — (0.04 ) (0.01 ) Net income attributable to EMCOR Group, Inc. common stockholders $ 5.78 $ 4.88 $ 3.84 Diluted earnings (loss) per common share: From continuing operations attributable to EMCOR Group, Inc. common stockholders $ 5.75 $ 4.89 $ 3.83 From discontinued operation — (0.04 ) (0.01 ) Net income attributable to EMCOR Group, Inc. common stockholders $ 5.75 $ 4.85 $ 3.82 The number of outstanding share-based awards excluded from the computation of diluted EPS for the years ended December 31, 2019 , 2018 , and 2017 because they would be anti-dilutive were 4,800 , 550 , and 2,700 , respectively.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2019
Inventory Disclosure [Abstract]
Inventories	INVENTORIES Inventories as of December 31, 2019 and 2018 consist of the following amounts (in thousands): 2019 2018 Raw materials and construction materials $ 31,365 $ 30,006 Work in process 9,081 12,315 Inventories $ 40,446 $ 42,321

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment in the accompanying Consolidated Balance Sheets consisted of the following amounts as of December 31, 2019 and 2018 (in thousands): 2019 2018 Machinery and equipment $ 166,087 $ 151,339 Vehicles 59,116 58,205 Furniture and fixtures 22,123 20,655 Computer hardware/software 104,916 98,415 Land, buildings and leasehold improvements 113,020 97,937 Construction in progress 10,236 14,443 Finance lease right-of-use assets (1) 9,609 — 485,107 440,994 Accumulated depreciation and amortization (328,920 ) (306,643 ) $ 156,187 $ 134,351 _________________ (1) Finance lease right-of-use assets are recorded net of accumulated amortization. Prior to the adoption of ASC 842 on January 1, 2019, assets under capital leases were recorded as machinery and equipment or computer hardware/software. Depreciation and amortization expense related to property, plant and equipment, including finance leases, was $43.9 million , $38.5 million , and $39.9 million for the years ended December 31, 2019 , 2018 , and 2017

Goodwill and Identifiable Intan

Goodwill and Identifiable Intangible Assets	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Identifiable Intangible Assets	GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS Goodwill at December 31, 2019 and 2018 was approximately $1,063.9 million and $990.9 million , respectively, and reflects the excess of the consideration transferred in a business combination over the fair value of the net assets acquired. Goodwill attributable to companies acquired in 2019 and 2018 has been valued at $72.7 million and $26.3 million , respectively. Accounting Standards Codification Topic 805, “Business Combinations” (“ASC 805”) requires that all business combinations be accounted for using the acquisition method and that certain identifiable intangible assets acquired in a business combination be recognized as assets apart from goodwill. Accounting Standards Codification Topic 350, “Intangibles-Goodwill and Other” (“ASC 350”) requires goodwill and other identifiable intangible assets with indefinite useful lives, such as trade names, not be amortized, but instead be tested at least annually for impairment (which we test each October 1, absent any earlier identified impairment indicators), and be written down if impaired. ASC 350 requires that goodwill be allocated to its respective reporting unit and that identifiable intangible assets with finite lives be amortized over their useful lives. As of December 31, 2019 , approximately 13.4% of our goodwill related to our United States electrical construction and facilities services segment, approximately 28.1% of our goodwill related to our United States mechanical construction and facilities services segment, approximately 27.2% of our goodwill related to our United States building services segment and approximately 31.3% of our goodwill related to our United States industrial services segment. We test for impairment of our goodwill at the reporting unit level. Our reporting units are consistent with the reportable segments identified in Note 19, “Segment Information,” of the notes to consolidated financial statements. In assessing whether our goodwill is impaired, we compare the fair value of the reporting unit to its carrying amount, including goodwill. If the fair value exceeds the carrying amount, no impairment loss is recognized. However, if the carrying amount of the reporting unit exceeds the fair value, the goodwill of the reporting unit is impaired and an impairment loss in the amount of the excess is recognized and charged to operations. The fair value of each of our reporting units is generally determined using discounted estimated future cash flows; however, in certain circumstances, consideration is given to a market approach whereby fair value is measured based on a multiple of earnings. For the years ended December 31, 2019 and 2018, no impairment of our goodwill was recognized. As part of our annual impairment testing for the year ended December 31, 2017, we recorded a non-cash impairment charge of $57.5 million within our United States industrial services segment. The weighted average cost of capital used in our annual testing for impairment as of October 1, 2019 was 9.5% , 9.1% and 10.5% for our domestic construction segments, our United States building services segment and our United States industrial services segment, respectively. The perpetual growth rate used for our annual testing was 2.7% for all of our domestic segments. Unfavorable changes in these key assumptions may affect future testing results. For example, keeping all other assumptions constant, a 50 basis point increase in the weighted average costs of capital would cause the estimated fair values of our United States electrical construction and facilities services segment, our United States mechanical construction and facilities services segment, our United States building services segment and our United States industrial services segment to decrease by approximately $108.8 million , $156.7 million , $98.0 million and $40.3 million , respectively. In addition, keeping all other assumptions constant, a 50 basis point reduction in the perpetual growth rate would cause the estimated fair values of our United States electrical construction and facilities services segment, our United States mechanical construction and facilities services segment, our United States building services segment and our United States industrial services segment to decrease by approximately $61.4 million , $90.5 million , $55.7 million and $20.5 million , respectively. Given the amounts by which the fair value exceeds the carrying value for each of our reporting units other than our United States industrial services segment, the decreases in estimated fair values described above would not have significantly impacted our 2019 impairment test. In the case of our United States industrial services segment, however, such decreases would cause the estimated fair value to approach its carrying value. We also test for the impairment of trade names that are not subject to amortization by calculating the fair value using the “relief from royalty payments” methodology. This approach involves two steps: (a) estimating reasonable royalty rates for each trade name and (b) applying these royalty rates to a net revenue stream and discounting the resulting cash flows to determine fair value. This fair value is then compared with the carrying value of each trade name. If the carrying amount of the trade name is greater than the implied fair value of the trade name, an impairment in the amount of the excess is recognized and charged to operations. For the years ended December 31, 2019 and 2018, no impairment of our indefinite-lived trade names was recognized. The annual impairment review of our indefinite-lived trade names for the year ended December 31, 2017 resulted in a $0.3 million non-cash impairment charge as a result of a change in the fair value of a subsidiary trade name associated with a prior acquisition reported within our United States building services segment. In addition, we review for the impairment of other identifiable intangible assets that are being amortized whenever facts and circumstances indicate that their carrying values may not be fully recoverable. This test compares their carrying values to the undiscounted pre-tax cash flows expected to result from the use of the assets. If the assets are impaired, the assets are written down to their fair values, generally determined based on their discounted estimated future cash flows. For the years ended December 31, 2019 and 2017, no impairment of our other identifiable intangible assets was recognized. For the year ended December 31, 2018, we recorded a $0.9 million non-cash impairment charge associated with a finite-lived trade name within our United States industrial services segment. Our development of the discounted future cash flow projections used in impairment testing is based upon assumptions and estimates by management from a review of our operating results and business plans, as well as forecasts of anticipated growth rates and margins, among other considerations. In addition, estimates of the weighted average cost of capital for each reporting unit are developed with the assistance of a third-party valuation specialist. Those assumptions and estimates can change in future periods and other factors used in assessing fair value, such as interest rates, are outside the control of management. There can be no assurance that estimates and assumptions made for purposes of our goodwill and identifiable intangible asset impairment testing will prove to be accurate predictions of the future. If our assumptions regarding future business performance including anticipated growth rates and margins are not achieved, or there is a rise in interest rates, we may be required to record goodwill and/or identifiable intangible asset impairment charges in future periods. It is not possible at this time to determine if any future impairment charge will result or, if it does, whether such a charge would be material to our results of operations. The changes in the carrying amount of goodwill by reportable segment during the years ended December 31, 2019 and 2018 were as follows (in thousands): United States electrical construction and facilities services segment United States mechanical construction and facilities services segment United States building services segment United States Total Balance at December 31, 2017 $ 125,707 $ 256,265 $ 255,733 $ 327,188 $ 964,893 Acquisitions, sales and purchase price adjustments 7,500 56 18,438 — 25,994 Balance at December 31, 2018 133,207 256,321 274,171 327,188 990,887 Acquisitions, sales and purchase price adjustments 9,338 48,699 14,987 — 73,024 Intersegment transfers — (5,800 ) — 5,800 — Balance at December 31, 2019 $ 142,545 $ 299,220 $ 289,158 $ 332,988 $ 1,063,911 The aggregate goodwill balance as of December 31, 2017 included $268.1 million of accumulated impairment charges, which were comprised of $139.5 million within the United States building services segment and $128.6 million within the United States industrial services segment. Identifiable intangible assets as of December 31, 2019 and 2018 consist of the following (in thousands): December 31, 2019 Gross Carrying Amount Accumulated Amortization Accumulated Impairment Charge Total Contract backlog $ 66,745 $ (61,651 ) $ — $ 5,094 Developed technology/Vendor network 95,661 (60,156 ) — 35,505 Customer relationships 644,755 (277,601 ) (4,834 ) 362,320 Trade names (amortized) 31,148 (21,830 ) — 9,318 Trade names (unamortized) 251,440 — (52,233 ) 199,207 Total $ 1,089,749 $ (421,238 ) $ (57,067 ) $ 611,444 December 31, 2018 Gross Carrying Amount Accumulated Amortization Accumulated Impairment Charge Total Contract backlog $ 58,945 $ (56,812 ) $ — $ 2,133 Developed technology/Vendor network 95,661 (55,318 ) — 40,343 Customer relationships 522,855 (240,073 ) (4,834 ) 277,948 Trade names (amortized) 31,148 (20,893 ) — 10,255 Trade names (unamortized) 209,840 — (52,233 ) 157,607 Total $ 918,449 $ (373,096 ) $ (57,067 ) $ 488,286 Identifiable intangible assets attributable to businesses acquired in 2019 and 2018 have been valued at $171.3 million and $36.6 million , respectively, and consist of contract backlog, customer relationships, and trade names. See Note 4 - Acquisitions of Businesses of the notes to consolidated financial statements for additional information with respect to acquisitions. Identifiable intangible amounts are amortized on a straight-line basis, as it best approximates the pattern in which the economic benefits of the identifiable intangible assets are consumed. The weighted average amortization periods for the unamortized balances remaining are, in the aggregate, approximately 8.5 years, which are comprised of the following: 0.75 years for contract backlog, 7.5 years for developed technology/vendor network, 8.75 years for customer relationships and 10.75 years for trade names. Amortization expense related to identifiable intangible assets with finite lives was $48.1 million , $42.4 million , and $48.6 million for the years ended December 31, 2019 , 2018 , and 2017 , respectively. The following table presents the estimated future amortization expense of identifiable intangible assets in the following years (in thousands): 2020 $ 56,680 2021 50,792 2022 48,589 2023 47,650 2024 47,300 Thereafter 161,226 $ 412,237

Debt

Debt	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Debt	DEBT Credit Agreement We have a credit agreement dated as of August 3, 2016 , which provides for a $900.0 million revolving credit facility (the “2016 Revolving Credit Facility”) and a $400.0 million term loan (the “2016 Term Loan”) (collectively referred to as the “2016 Credit Agreement”) expiring August 3, 2021 . We may increase the 2016 Revolving Credit Facility to $1.3 billion if additional lenders are identified and/or existing lenders are willing to increase their current commitments. We may allocate up to $300.0 million of available capacity under the 2016 Revolving Credit Facility to letters of credit for our account or for the account of any of our subsidiaries. Obligations under the 2016 Credit Agreement are guaranteed by most of our direct and indirect subsidiaries and are secured by substantially all of our assets. The 2016 Credit Agreement contains various covenants providing for, among other things, maintenance of certain financial ratios and certain limitations on payment of dividends, common stock repurchases, investments, acquisitions, indebtedness and capital expenditures. We were in compliance with all such covenants as of December 31, 2019 and 2018. A commitment fee is payable on the average daily unused amount of the 2016 Revolving Credit Facility, which ranges from 0.15% to 0.30% , based on certain financial tests. The fee was 0.15% of the unused amount as of December 31, 2019 . Borrowings under the 2016 Credit Agreement bear interest at (1) a base rate plus a margin of 0.00% to 0.75% , based on certain financial tests, or (2) United States dollar LIBOR ( 1.80% at December 31, 2019 ) plus 1.00% to 1.75% , based on certain financial tests. The base rate is determined by the greater of (a) the prime commercial lending rate announced by Bank of Montreal from time to time ( 4.75% at December 31, 2019 ), (b) the federal funds effective rate, plus ½ of 1.00% , (c) the daily one month LIBOR rate, plus 1.00% , or (d) 0.00% .The interest rate in effect at December 31, 2019 was 2.80% . Fees for letters of credit issued under the 2016 Revolving Credit Facility range from 1.00% to 1.75% of the respective face amounts of outstanding letters of credit and are computed based on certain financial tests. Debt issuance costs are amortized over the life of the agreement and are included as part of interest expense. The 2016 Term Loan previously required us to make principal payments of $5.0 million on the last day of March, June, September and December of each year, which commenced with the calendar quarter ended December 31, 2016. On December 30, 2016, we made a payment of $100.0 million , of which $5.0 million represented our required quarterly payment and $95.0 million represented a prepayment of outstanding principal. Such prepayment was applied against the remaining mandatory quarterly payments on a ratable basis. As a result, commencing with the calendar quarter ended March 31, 2017, our required quarterly payment has been reduced to $3.8 million . All unpaid principal and interest is due on August 3, 2021. As of December 31, 2019 and 2018 , the balance of the 2016 Term Loan was $254.4 million and $269.6 million , respectively. As of December 31, 2019 and 2018 , we had approximately $109.0 million of letters of credit outstanding. There were $50.0 million and $25.0 million in borrowings outstanding under the 2016 Revolving Credit Facility as of December 31, 2019 and December 31, 2018 , respectively. Long-term debt in the accompanying Consolidated Balance Sheets consisted of the following amounts as of December 31, 2019 and 2018 (in thousands): 2019 2018 Revolving credit facility $ 50,000 $ 25,000 Term loan, interest payable at varying amounts through 2021 254,431 269,620 Unamortized debt issuance costs (1,879 ) (3,065 ) Finance lease liabilities 9,679 4,213 Other — 9 Total debt 312,231 295,777 Less: current maturities 18,092 16,013 Total long-term debt $ 294,139 $ 279,764 Finance Lease Liabilities

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS We use a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy, which gives the highest priority to quoted prices in active markets, is comprised of the following three levels: Level 1 – Unadjusted quoted market prices in active markets for identical assets and liabilities. Level 2 – Observable inputs, other than Level 1 inputs. Level 2 inputs would typically include quoted prices in markets that are not active or financial instruments for which all significant inputs are observable, either directly or indirectly. Level 3 – Prices or valuations that require inputs that are both significant to the measurement and unobservable. The following tables provide the assets and liabilities carried at fair value measured on a recurring basis as of December 31, 2019 and 2018 (in thousands): Assets at Fair Value as of December 31, 2019 Asset Category Level 1 Level 2 Level 3 Total Cash and cash equivalents (1) $ 358,818 $ — $ — $ 358,818 Restricted cash (2) 1,102 — — 1,102 Deferred compensation plan assets (3) 30,295 — — 30,295 Total $ 390,215 $ — $ — $ 390,215 Assets at Fair Value as of December 31, 2018 Asset Category Level 1 Level 2 Level 3 Total Cash and cash equivalents (1) $ 363,907 $ — $ — $ 363,907 Restricted cash (2) 2,307 — — 2,307 Deferred compensation plan assets (3) 23,124 — — 23,124 Total $ 389,338 $ — $ — $ 389,338 _________________ (1) Cash and cash equivalents consist of deposit accounts and money market funds with original maturity dates of three months or less, which are Level 1 assets. At December 31, 2019 and 2018 , we had $164.0 million and $161.3 million , respectively, in money market funds. (2) Restricted cash is classified as “Prepaid expenses and other” in the Consolidated Balance Sheets. Restricted cash primarily represents cash held in account for use on customer contracts. (3) Deferred compensation plan assets are classified as “Other assets” in the Consolidated Balance Sheets. We believe that the carrying values of our financial instruments, which include accounts receivable and other financing commitments, approximate their fair values due primarily to their short-term maturities and low risk of counterparty default. The carrying value of our debt associated with the 2016 Credit Agreement approximates its fair value due to the variable rate on such debt.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES On December 22, 2017, the U.S. government enacted comprehensive tax legislation, commonly referred to as the Tax Cuts and Jobs Act (“the Tax Act”). The Tax Act made broad and complex changes to the U.S. tax code, including, among other things, reducing the U.S. federal corporate tax rate from 35% to 21% , eliminating certain deductions including the domestic manufacturing deduction, providing additional limitations on deductions for executive compensation, imposing a mandatory one-time transition tax on accumulated earnings from certain foreign subsidiaries, and creating new taxes on certain foreign sourced earnings. The Tax Act also extended the option to claim accelerated depreciation deductions by allowing companies to fully deduct qualified property in the year such property is placed in service. In 2018, we finalized our accounting for the income tax effects of the Tax Act, for which we had previously recorded provisional amounts in our 2017 consolidated financial statements in accordance with Staff Accounting Bulletin No. 118. During the year ended December 31, 2017, our net federal and state deferred tax liability balances were reduced by approximately $39.3 million , which was recorded as a reduction of income tax expense in the Company’s Consolidated Statements of Operations, as U.S. generally accepted accounting principles required a re-measurement of our deferred tax assets and liabilities as of the date of enactment. We continue to monitor for potential future changes in certain state and local tax regulations resulting from the Tax Act which may have an impact on our consolidated income tax provision in future periods. For the years ended December 31, 2019 , 2018 , and 2017 , our income tax provision was calculated based on income from continuing operations before income taxes as follows (in thousands): 2019 2018 2017 United States $ 430,253 $ 375,408 $ 303,854 Foreign 20,636 19,620 14,895 $ 450,889 $ 395,028 $ 318,749 The income tax provision in the accompanying Consolidated Statements of Operations for the years ended December 31, 2019 , 2018 , and 2017 consisted of the following (in thousands): 2019 2018 2017 Current provision: Federal $ 89,264 $ 75,405 $ 120,317 State and local 31,099 28,063 23,496 Foreign 3,685 1,389 244 124,048 104,857 144,057 Deferred provision (benefit) 1,701 4,249 (53,358 ) $ 125,749 $ 109,106 $ 90,699 Our 2019 income tax provision from continuing operations was $125.7 million compared to $109.1 million for 2018 and $90.7 million for 2017 . The increase in the income tax provision for each year was primarily driven by increased income from continuing operations before income taxes. The actual income tax rates on income from continuing operations before income taxes, less amounts attributable to noncontrolling interests, for the years ended December 31, 2019 , 2018 , and 2017 , were 27.9% , 27.6% , and 28.5% , respectively. The increase in the 2019 actual income tax rate compared to 2018 was predominantly due to: (a) an increase in our state deferred tax rate, partially as a result of a change in the mix of income, and (b) the continued application of the Tax Act, including the application of guidance regarding certain permanent differences and other nondeductible expenses. The decrease in the 2018 actual income tax rate compared to 2017 was due to the net impact of the Tax Act, including the reduction of the U.S. federal corporate tax rate from 35% to 21% in 2018, partially offset by the reduction in income tax expense associated with the re-measurement of our net deferred tax liability balance in 2017. Items accounting for the differences between income taxes computed at the federal statutory rate and the income tax provision for the years ended December 31, 2019 , 2018 , and 2017 were as follows (in thousands): 2019 2018 2017 Federal income taxes at the statutory rate $ 94,687 $ 82,946 $ 111,562 State and local income taxes, net of federal tax benefits 24,904 21,827 15,736 State tax reserves — (7 ) (2,543 ) Permanent differences 7,149 6,584 4,916 Domestic manufacturing deduction — — (10,387 ) Excess tax benefit from share-based compensation (733 ) (1,227 ) (1,341 ) Goodwill impairment — — 17,055 Foreign income taxes (including UK statutory rate changes) (170 ) 70 (2,586 ) Impact of federal rate change on net deferred tax liabilities — — (39,343 ) Federal tax reserves — (67 ) (1,247 ) Other (88 ) (1,020 ) (1,123 ) $ 125,749 $ 109,106 $ 90,699 Our income tax provision for the year ended December 31, 2019 and 2018 included $0.1 million and $0.6 million , respectively, for the minimum tax on global intangible low-taxed income for certain earnings of our foreign subsidiaries, as required under the Tax Act. The Company has elected to recognize such tax as an expense in the period incurred. As of December 31, 2019, we had undistributed foreign earnings from certain foreign subsidiaries of approximately $69.8 million . Based on our evaluation, and given that a significant portion of such earnings were subject to tax in prior periods or are indefinitely reinvested, we have concluded that any taxes associated with the repatriation of such foreign earnings would be immaterial. As of December 31, 2019, the amount of cash held by these foreign subsidiaries was approximately $67.7 million which, if repatriated, should not result in any federal or state income taxes. Tax benefits associated with uncertain tax positions are recognized only if it is “more likely than not” that the tax position would be sustained on its technical merits. For positions not meeting the “more likely than not” test, no tax benefit is recognized. As of December 31, 2019 and 2018, we had no unrecognized income tax benefits. We file a consolidated federal income tax return including all of our U.S. subsidiaries with the Internal Revenue Service. We additionally file income tax returns with various state, local, and foreign tax agencies. The Company is currently under examination by various taxing authorities for the years 2014 through 2018. Deferred income tax assets and liabilities are recognized in the Consolidated Balance Sheets for the expected future tax consequences of temporary differences between the carrying amounts and the tax bases of assets and liabilities. The deferred income tax assets and deferred income tax liabilities recorded for the years ended December 31, 2019 and 2018 were as follows (in thousands): 2019 2018 Deferred income tax assets: Excess of amounts expensed for financial statement purposes over amounts deducted for income tax purposes: Insurance liabilities $ 47,022 $ 44,192 Pension liability 2,733 3,204 Operating lease liabilities (1) 68,158 — Deferred compensation 32,685 29,300 Other (including liabilities and reserves) 25,647 27,400 Total deferred income tax assets 176,245 104,096 Valuation allowance for deferred tax assets (3,463 ) (3,855 ) Net deferred income tax assets 172,782 100,241 Deferred income tax liabilities: Costs capitalized for financial statement purposes and deducted for income tax purposes: Goodwill and identifiable intangible assets (156,604 ) (152,761 ) Operating lease right-of-use assets (1) (65,090 ) — Depreciation of property, plant and equipment (18,622 ) (14,904 ) Other (4,212 ) (3,424 ) Total deferred income tax liabilities (244,528 ) (171,089 ) Net deferred income tax liabilities $ (71,746 ) $ (70,848 ) _________________ (1) As discussed in Note 2 - Summary of Significant Accounting Policies of the notes to consolidated financial statements, on January 1, 2019, we adopted the accounting pronouncement issued by the Financial Accounting Standards Board (“FASB”), which required lessees to record right-of-use assets and corresponding lease liabilities on the balance sheet for most leases. We adopted this pronouncement utilizing the transition practical expedient added by the FASB, which eliminated the requirement that entities apply the new lease standard to the comparative periods presented in the year of adoption. The components of the net deferred income tax liabilities in the accompanying Consolidated Balance Sheets are included in “Other assets” in the amount of $3.4 million and $4.7 million and “Other long-term obligations” in the amount of $75.2 million and $75.5 million , at December 31, 2019 and 2018 , respectively. Valuation allowances are established when necessary to reduce deferred income tax assets when it is more likely than not that a tax benefit will not be realized. As of December 31, 2019 and 2018 , the total valuation allowance on deferred income tax assets was approximately $3.5 million and $3.9 million , respectively, related to state and local net operating losses. Although realization is not assured, we believe it is more likely than not that the deferred income tax assets, net of the valuation allowance discussed above, will be realized. The amount of the deferred income tax assets considered realizable, however, could be reduced if estimates of future income are reduced. At December 31, 2019, there are no longer any trading losses available for United Kingdom income tax purposes. At December 31, 2018, we had trading losses for United Kingdom income tax purposes of approximately $4.2 million , which were utilized in 2019 and are subject to review by the United Kingdom taxing authority.

Common Stock

Common Stock	12 Months Ended
	Dec. 31, 2019
Stockholders' Equity Note [Abstract]
Common Stock	COMMON STOCK As of December 31, 2019 and 2018 , there were 56,219,831 and 55,983,763 shares of our common stock outstanding, respectively. We have paid quarterly dividends since October 25, 2011. We currently pay a regular quarterly dividend of $0.08 per share. On September 26, 2011, our Board of Directors (the “Board”) authorized us to repurchase up to $100.0 million of our outstanding common stock. Subsequently, the Board has from time to time increased the amount of our common stock that we may repurchase. Since the inception of the repurchase program, the Board has authorized us to repurchase up to $950.0 million of our outstanding common stock. No shares of our common stock were repurchased during the year ended December 31, 2019. Since the inception of the repurchase program through December 31, 2019, we have repurchased approximately 15.9 million shares of our common stock for approximately $791.5 million . As of December 31, 2019, there remained authorization for us to repurchase approximately $158.5 million of our shares. The repurchase program has no expiration date and does not obligate the Company to acquire any particular amount of common stock and may be suspended, recommenced or discontinued at any time or from time to time without prior notice. We may repurchase our shares from time to time to the extent permitted by securities laws and other legal requirements, including provisions in our 2016 Credit Agreement placing limitations on such repurchases. The repurchase program has been and will be funded from our operations.

Share-Based Compensation Plans

Share-Based Compensation Plans	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Share-Based Compensation Plans	SHARE-BASED COMPENSATION PLANS We have an incentive plan under which stock options, stock awards, stock units and other share-based compensation may be granted to officers, non-employee directors and key employees of the Company. Under the terms of this plan, 3,250,000 shares were authorized, and 1,160,086 shares are available for grant or issuance as of December 31, 2019 . Any issuances under this plan are valued at the fair market value of the common stock on the grant date. The vesting and expiration of any stock option grants and the vesting schedule of any stock awards or stock units are determined by the Compensation and Personnel Committee of our Board of Directors at the time of the grant. Forfeitures are recognized as they occur. The following table summarizes activity regarding our stock options and awards of shares and stock units since December 31, 2016: Stock Options Restricted Stock Units Shares Weighted Average Price Shares Weighted Average Price Balance, December 31, 2016 143,000 $ 23.06 Balance, December 31, 2016 492,288 $ 44.93 Granted — — Granted 198,179 $ 68.33 Expired — — Forfeited (1,200 ) $ 60.68 Exercised (50,000 ) $ 20.42 Vested (180,395 ) $ 44.57 Balance, December 31, 2017 93,000 $ 24.48 Balance, December 31, 2017 508,872 $ 54.13 Granted — — Granted 135,259 $ 80.37 Expired — — Forfeited (1,250 ) $ 71.27 Exercised (53,000 ) $ 24.48 Vested (166,295 ) $ 48.44 Balance, December 31, 2018 40,000 $ 24.48 Balance, December 31, 2018 476,586 $ 63.52 Granted — — Granted 169,766 $ 64.34 Expired — — Forfeited (2,545 ) $ 71.88 Exercised (20,000 ) $ 24.48 Vested (226,229 ) $ 51.64 Balance, December 31, 2019 20,000 $ 24.48 Balance, December 31, 2019 417,578 $ 70.24 We recognized approximately $11.4 million , $11.0 million , and $9.9 million of compensation expense for stock units awarded to non-employee directors and employees pursuant to incentive plans for the years ended December 31, 2019 , 2018 , and 2017 , respectively. We have approximately $8.7 million of compensation expense, net of income taxes, which will be recognized over the remaining vesting periods of up to approximately 3 years . In addition, an aggregate of 72,310 restricted stock units granted to non-employee directors vested as of December 31, 2019, but issuance has been deferred up to 5 years . All outstanding stock options were fully vested; therefore, no compensation expense was recognized with respect to stock options for the years ended December 31, 2019, 2018, and 2017. The income tax benefit derived in 2019 , 2018 , and 2017 as a result of stock option exercises and other share-based compensation was approximately $2.6 million , $3.6 million , and $3.9 million , respectively, of which approximately $1.0 million , $1.6 million , and $1.6 million , respectively, represented excess tax benefits. The total intrinsic value of options (the amounts by which the stock price exceeded the exercise price of the option on the date of exercise) that were exercised during 2019 , 2018 , and 2017 was approximately $1.2 million , $2.7 million , and $2.3 million , respectively. At December 31, 2019 , 2018 , and 2017 , 20,000 options, 40,000 options and 93,000 options were outstanding and exercisable, respectively. The weighted average exercise price for all such options was $24.48 . The total aggregate intrinsic value of options outstanding and exercisable as of December 31, 2019 , 2018 , and 2017 were approximately $1.2 million , $1.4 million , and $5.3 million , respectively. The following table summarizes information about our outstanding stock options as of December 31, 2019 : Stock Options Outstanding and Exercisable Range of Exercise Prices Number Weighted Average Remaining Life Weighted Average Exercise Price $24.48 20,000 0.45 Years $24.48 We have an employee stock purchase plan. Under the terms of this plan, the maximum number of shares of our common stock that may be purchased is 3,000,000

Retirement Plans

Retirement Plans	12 Months Ended
	Dec. 31, 2019
Retirement Benefits [Abstract]
Retirement Plans	RETIREMENT PLANS Defined Benefit Plans Our United Kingdom subsidiary has a defined benefit pension plan covering all eligible employees (the “UK Plan”); however, no individual joining the company after October 31, 2001 may participate in the UK Plan. On May 31, 2010, we curtailed the future accrual of benefits for active employees under this plan. We account for the UK Plan and other defined benefit plans in accordance with Accounting Standards Codification Topic 715, “Compensation-Retirement Benefits” (“ASC 715”). ASC 715 requires that (a) the funded status, which is measured as the difference between the fair value of plan assets and the projected benefit obligations, be recorded in our balance sheet with a corresponding adjustment to accumulated other comprehensive income (loss) and (b) gains and losses for the differences between actuarial assumptions and actual results, and unrecognized service costs, be recognized through accumulated other comprehensive income (loss). These amounts will be subsequently recognized as net periodic pension cost. The change in benefit obligations and assets of the UK Plan for the years ended December 31, 2019 and 2018 consisted of the following components (in thousands): 2019 2018 Change in pension benefit obligation Benefit obligation at beginning of year $ 281,776 $ 332,618 Interest cost 7,961 8,085 Actuarial loss (gain) 32,866 (27,755 ) Benefits paid (12,059 ) (14,318 ) Foreign currency exchange rate changes 12,222 (16,854 ) Benefit obligation at end of year 322,766 281,776 Change in pension plan assets Fair value of plan assets at beginning of year 264,194 295,968 Actual return on plan assets 38,808 (6,489 ) Employer contributions 4,428 4,742 Benefits paid (12,059 ) (14,318 ) Foreign currency exchange rate changes 11,630 (15,709 ) Fair value of plan assets at end of year 307,001 264,194 Funded status at end of year $ (15,765 ) $ (17,582 ) Amounts not yet reflected in net periodic pension cost and included in accumulated other comprehensive loss were as follows (in thousands): 2019 2018 Unrecognized losses $ 94,211 $ 86,768 The underfunded status of the UK Plan of $15.8 million and $17.6 million at December 31, 2019 and 2018 , respectively, is included in “Other long-term obligations” in the accompanying Consolidated Balance Sheets. No plan assets are expected to be returned to us during the year ending December 31, 2020. The weighted average assumptions used to determine benefit obligations as of December 31, 2019 and 2018 were as follows: 2019 2018 Discount rate 2.1 % 2.9 % The weighted average assumptions used to determine net periodic pension cost for the years ended December 31, 2019 , 2018 , and 2017 were as follows: 2019 2018 2017 Discount rate 2.9 % 2.5 % 2.7 % Annual rate of return on plan assets 4.9 % 5.0 % 5.3 % The annual rate of return on plan assets has been determined by modeling possible returns using the actuary’s portfolio return calculator and the fair value of plan assets. This models the long term expected returns of the various asset classes held in the portfolio and takes into account the additional benefits of holding a diversified portfolio. For measurement purposes of the liability, the annual rates of inflation of covered pension benefits assumed for 2019 and 2018 were 2.0% and 2.1% , respectively. The components of net periodic pension cost (income) of the UK Plan for the years ended December 31, 2019 , 2018 , and 2017 were as follows (in thousands): 2019 2018 2017 Interest cost $ 7,961 $ 8,085 $ 8,622 Expected return on plan assets (12,165 ) (13,797 ) (13,508 ) Amortization of unrecognized loss 2,342 2,630 2,942 Net periodic pension cost (income) $ (1,862 ) $ (3,082 ) $ (1,944 ) Actuarial gains and losses are amortized using a corridor approach whereby cumulative gains and losses in excess of the greater of 10% of the pension benefit obligation or the fair value of plan assets are amortized over the average life expectancy of plan participants. The amortization period for 2019 was 25 years. The reclassification adjustment, net of income taxes, for the UK Plan from accumulated other comprehensive loss into net periodic pension cost for the years ended December 31, 2019, 2018, and 2017 was approximately $1.9 million , $2.1 million , and $2.3 million , respectively. The estimated unrecognized loss for the UK Plan that will be amortized from accumulated other comprehensive loss into net periodic pension cost over the next year is approximately $2.0 million , net of income taxes. UK Plan Assets The investment policies and strategies for the assets of the UK Plan are established by its trustees (who are independent of the Company) to achieve a reasonable balance between risk, likely return, and administration expense, as well as to maintain funds at a level to meet minimum funding requirements. In order to ensure that an appropriate investment strategy is in place, an analysis of the UK Plan’s assets and liabilities is completed periodically. Target allocation percentages vary over time depending on the perceived risk and return potential of various asset classes and market conditions. The weighted average asset allocations and weighted average target allocations at December 31, 2019 and 2018 were as follows: Asset Category Target December 31, December 31, Debt 65.0 % 70.6 % 71.2 % Equity 15.0 % 10.5 % 13.4 % Cash 10.0 % 10.5 % 6.1 % Real estate 10.0 % 8.4 % 9.3 % Total 100.0 % 100.0 % 100.0 % Plan assets of our UK Plan are invested through third-party fund managers in various investments with underlying holdings which consist of: (a) debt securities, which include United Kingdom government debt and United States, United Kingdom, European and emerging market corporate debt, (b) equity securities, which include marketable equity and equity like instruments across developed global equity markets, and (c) real estate assets, which represent trusts which invest directly or indirectly in various properties throughout the United Kingdom. Assets of the UK Plan are allocated within the fair value hierarchy discussed in Note 11 - Fair Value Measurements, based on the nature of the investment. Level 1 assets represent cash. Level 2 assets consist of corporate debt funds, government bond funds, and equity funds whose underlying investments are valued using observable marketplace inputs. The fair value of the level 2 assets are generally determined under a market approach using valuation models that incorporate observable inputs such as interest rates, bond yields, and quoted prices. Investments valued using net asset value (“NAV”) as a practical expedient are excluded from the fair value hierarchy. These investments include: (a) funds which invest predominantly in senior secured debt instruments, targeting diversity across regions and sectors, as well as funds which invest in diversified credit vehicles that seek higher returns than traditional fixed income, primarily through investments in U.S. corporate debt, global credit, and structured debt, and (b) funds which aim to provide long-term income through investment in UK property assets. These investments are redeemable at NAV on a monthly or quarterly basis and have redemption notice periods of up to 90 days. In addition, certain of these investments are subject to a lockup period of up to 24 months. The methods described above may produce fair values that may not be indicative of net realizable value or reflective of future fair values. Furthermore, while the Company believes the valuation methodologies are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine fair value of certain financial instruments could result in a different fair value measurement at the reporting date. The following tables set forth the fair value of assets of the UK Plan as of December 31, 2019 and 2018 (in thousands): Assets at Fair Value as of December 31, 2019 Asset Category Level 1 Level 2 Level 3 Total Corporate debt funds $ — $ 64,314 $ — $ 64,314 Government bond funds — 49,164 — 49,164 Equity funds — 32,356 — 32,356 Cash 32,240 — — 32,240 Total plan assets in fair value hierarchy $ 32,240 $ 145,834 $ — 178,074 Plan assets measured using NAV as a practical expedient: (1) Debt funds 103,188 Real estate funds 25,739 Total plan assets at fair value $ 307,001 Assets at Fair Value as of December 31, 2018 Asset Category Level 1 Level 2 Level 3 Total Corporate debt funds $ — $ 37,703 $ — $ 37,703 Government bond funds — 52,445 — 52,445 Equity funds — 35,425 — 35,425 Cash 16,097 — — 16,097 Total plan assets in fair value hierarchy $ 16,097 $ 125,573 $ — 141,670 Plan assets measured using NAV as a practical expedient: (1) Debt funds 98,077 Real estate funds 24,447 Total plan assets at fair value $ 264,194 _________________ (1) Certain investments measured using NAV as a practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in the table are intended to permit reconciliation of the fair value hierarchy to the total fair value of plan assets. Cash Flows: Contributions Our United Kingdom subsidiary expects to contribute approximately $4.8 million to the UK Plan in 2020. Estimated Future Benefit Payments The following estimated benefit payments are expected to be paid in the following years (in thousands): Pension Benefit Payments 2020 $ 12,887 2021 $ 13,240 2022 $ 13,603 2023 $ 13,976 2024 $ 14,358 Succeeding five years $ 77,912 The following table shows certain information for the UK Plan where the accumulated benefit obligation is in excess of plan assets as of December 31, 2019 and 2018 (in thousands): 2019 2018 Projected benefit obligation $ 322,766 $ 281,776 Accumulated benefit obligation $ 322,766 $ 281,776 Fair value of plan assets $ 307,001 $ 264,194 We also sponsor three domestic retirement plans in which participation by new individuals is frozen. The benefit obligation associated with these plans as of December 31, 2019 and 2018 was approximately $9.2 million and $8.5 million , respectively. The estimated fair value of the plan assets as of December 31, 2019 and 2018 was approximately $5.7 million and $4.9 million , respectively. The plan assets are considered Level 1 assets within the fair value hierarchy and are predominantly invested in cash, equities, and equity and bond funds. The liability balances as of December 31, 2019 and 2018 are classified as “Other long-term obligations” in the accompanying Consolidated Balance Sheets. The measurement date for these plans is December 31 of each year. The major assumptions used in the actuarial valuations to determine benefit obligations as of December 31, 2019 and 2018 included discount rates of 3.00% to 4.00% for 2019 and 4.00% to 4.25% for 2018. Also, included was an expected rate of return of 7.00% for both 2019 and 2018 . The net periodic pension cost associated with the domestic plans was approximately $0.3 million for each of the years ended December 31, 2019 and 2018. The reclassification adjustment, net of income taxes, from accumulated other comprehensive loss into net periodic pension cost was approximately $0.2 million for each of the years ended December 31, 2019 , 2018 , and 2017 . The estimated loss for these plans that will be amortized from accumulated other comprehensive loss into net periodic pension cost over the next year is approximately $0.3 million , net of income taxes. The future estimated benefit payments expected to be paid from the plans for the next ten years is approximately $0.6 million per year. Multiemployer Plans We participate in approximately 200 multiemployer pension plans (“MEPPs”) that provide retirement benefits to certain union employees in accordance with various collective bargaining agreements (“CBAs”). As one of many participating employers in an MEPP, we are potentially liable with the other participating employers for such plan's underfunding either through an increase in our required contributions, or in the case of our withdrawal from the plan, a payment based upon our proportionate share of the plan's unfunded benefits, in each case, as described below. Our contributions to a particular MEPP are established by the applicable CBAs; however, our required contributions may increase based on the funded status of an MEPP and legal requirements of the Pension Protection Act of 2006 (the “PPA”), which requires substantially underfunded MEPPs to implement a funding improvement plan (“FIP”) or a rehabilitation plan (“RP”) to improve their funded status. Factors that could impact the funded status of an MEPP include, without limitation, investment performance, changes in the participant demographics, decline in the number of contributing employers, changes in actuarial assumptions and the utilization of extended amortization provisions. An FIP or RP requires a particular MEPP to adopt measures to correct its underfunding status. These measures may include, but are not limited to: (a) an increase in our contribution rate as a signatory to the applicable CBA, (b) a reallocation of the contributions already being made by participating employers for various benefits to individuals participating in the MEPP, and/or (c) a reduction in the benefits to be paid to future and/or current retirees. In addition, the PPA requires that a 5% surcharge be levied on employer contributions for the first year commencing after the date the employer receives notice that the MEPP is in critical status and a 10% surcharge on each succeeding year until a CBA is in place with terms and conditions consistent with the RP. We could also be obligated to make payments to MEPPs if we either cease to have an obligation to contribute to the MEPP or significantly reduce our contributions to the MEPP because we reduce our number of employees who are covered by the relevant MEPP for various reasons, including, but not limited to, layoffs or closure of a subsidiary assuming the MEPP has unfunded vested benefits. The amount of such payments (known as a complete or partial withdrawal liability) would equal our proportionate share of the MEPPs’ unfunded vested benefits. We believe that certain of the MEPPs in which we participate may have unfunded vested benefits. Due to uncertainty regarding future factors that could trigger withdrawal liability, as well as the absence of specific information regarding the MEPP’s current financial situation, we are unable to determine (a) the amount and timing of a future withdrawal liability, if any, and (b) whether our participation in these MEPPs could have a material adverse impact on our financial position, results of operations or liquidity. We did not record any withdrawal liability for the years ended December 31, 2019 , 2018 , and 2017 . The following table lists all domestic MEPPs to which our contributions exceeded $2.0 million in 2019 . Additionally, this table also lists all domestic MEPPs to which we contributed in 2019 in excess of $0.5 million for MEPPs in the critical status, “red zone,” and $1.0 million for MEPPs in the endangered status, “orange or yellow zones,” as defined by the PPA (in thousands): Pension Fund EIN/Pension Plan Number PPA Zone Status (1) FIP/RP Status Contributions Contributions greater than 5% of total plan contributions (2) Expiration date or range of expiration dates of CBA(s) 2019 2018 2019 2018 2017 National Electrical Benefit Fund 53-0181657 001 Green Green NA $ 16,901 $ 10,700 $ 11,572 No January 2020 to National Automatic Sprinkler Industry Pension Fund 52-6054620 001 Red Red Implemented 15,924 14,888 14,228 No June 2020 to June 2022 Plumbers & Pipefitters National Pension Fund 52-6152779 001 Yellow Yellow Implemented 13,821 11,868 12,550 No February 2020 to August 2026 Sheet Metal Workers National Pension Fund 52-6112463 001 Yellow Yellow Implemented 11,713 10,895 12,895 No April 2020 to Pension, Hospitalization & Benefit Plan of the Electrical Industry-Pension Trust Account 13-6123601 001 Green Green NA 10,075 10,469 9,489 No April 2020 to April 2022 Electrical Workers Local No. 26 Pension Trust Fund 52-6117919 001 Green Green NA 8,434 5,485 4,441 Yes January 2020 to July 2021 Plumbers Pipefitters & Mechanical Equipment Service Local Union 392 Pension Plan 31-0655223 001 Red Red Implemented 6,412 6,047 6,084 Yes June 2022 Southern California IBEW-NECA Pension Trust Fund 95-6392774 001 Yellow Yellow Implemented 6,277 5,754 3,669 No May 2020 to Central Pension Fund of the IUOE & Participating Employers 36-6052390 001 Green Green NA 6,253 6,384 6,070 No February 2020 to Sheet Metal Workers Pension Plan of Northern California 51-6115939 001 Red Red Implemented 6,233 5,488 6,023 No June 2020 to June 2026 Arizona Pipe Trades Pension Trust Fund 86-6025734 001 Green Green NA 6,071 2,640 1,662 Yes June 2020 Edison Pension Plan 93-6061681 001 Green Green NA 5,361 3,140 1,628 Yes December 2020 Pipefitters Union Local 537 Pension Fund 51-6030859 001 Green Green NA 4,754 6,038 4,057 Yes September 2020 to August 2021 Pension Fund EIN/Pension Plan Number PPA Zone Status (1) FIP/RP Status Contributions Contributions greater than 5% of total plan contributions (2) Expiration date or range of expiration dates of CBA(s) 2019 2018 2019 2018 2017 Heating, Piping & Refrigeration Pension Fund 52-1058013 001 Green Green NA 4,185 2,619 2,437 No June 2020 to July 2021 U.A. Local 393 Pension Trust Fund Defined Benefit 94-6359772 002 Green Green NA 3,858 4,298 1,540 Yes June 2020 to June 2021 San Diego Electrical Pension Plan 95-6101801 001 Green Green NA 3,843 3,008 2,862 Yes May 2020 to May 2022 Eighth District Electrical Pension Fund 84-6100393 001 Green Green NA 3,590 3,486 3,786 Yes May 2020 to May 2022 Southern California Pipe Trades Retirement Fund 51-6108443 001 Green Green NA 3,274 3,095 3,907 No June 2020 to Electrical Contractors Association and Local Union 134, IBEW Joint Pension Trust of Chicago Pension Plan 2 51-6030753 002 Green Green NA 3,204 4,308 5,537 No May 2020 Northern California Pipe Trades Pension Plan 94-3190386 001 Green Green NA 3,077 3,104 2,963 No June 2020 to June 2021 NECA-IBEW Pension Trust Fund 51-6029903 001 Green Green NA 2,528 2,650 3,060 No May 2020 to December 2020 U.A. Plumbers Local 24 Pension Fund 22-6042823 001 Green Green NA 2,460 3,461 3,092 Yes April 2020 Sheet Metal Workers Pension Plan of Southern California, Arizona & Nevada 95-6052257 001 Yellow Yellow Implemented 2,423 1,934 3,268 No June 2020 to June 2024 Connecticut Plumbers & Pipefitters Pension Fund 06-6050353 001 Green Green NA 2,231 2,104 1,988 Yes June 2021 U.A. Local 38 Defined Benefit Pension Plan 94-1285319 001 Green Green NA 2,030 1,551 2,097 No June 2020 to June 2023 Plumbing & Pipe Fitting Local 219 Pension Fund 34-6682376 001 Red Red Implemented 1,937 2,197 1,335 Yes May 2020 Boilermaker-Blacksmith National Pension Trust 48-6168020 001 Red Red Implemented 1,681 1,446 1,083 No September 2020 to Plumbers & Pipefitters Local Union No. 502 & 633 Pension Fund 61-6078145 001 Yellow Yellow Implemented 1,596 1,167 801 No May 2020 to July 2022 Plumbers & Pipefitters Local 162 Pension Fund 31-6125999 001 Yellow Yellow Implemented 1,124 1,273 801 Yes May 2020 to May 2022 Steamfitters Local Union No. 420 Pension Plan 23-2004424 001 Red Red Implemented 641 706 687 No May 2020 Other Multiemployer Pension Plans 53,567 48,026 43,604 Various Total Contributions $ 215,478 $ 190,229 $ 179,216 _________________ (1) The zone status represents the most recent available information for the respective MEPP, which may be 2018 or earlier for the 2019 year and 2017 or earlier for the 2018 year. (2) This information was obtained from the respective plan’s Form 5500 (“Forms”) for the most current available filing. These dates may not correspond with our fiscal year contributions. The above noted percentages of contributions are based upon disclosures contained in the plans’ Forms. Those Forms, among other things, disclose the names of individual participating employers whose annual contributions account for more than 5% of the aggregate annual amount contributed by all participating employers for a plan year. Accordingly, if the annual contribution of two or more of our subsidiaries each accounted for less than 5% of such contributions, but in the aggregate accounted for in excess of 5% of such contributions, that greater percentage is not available and accordingly is not disclosed. The nature and diversity of our operations may result in volatility in the amount of our contributions to a particular MEPP for any given period. That is because, in any given market, a change in the mix, volume of, or size of our projects could result in a change in our direct labor force and a corresponding change in our contributions to the MEPP(s) dictated by the applicable CBA. Additionally, the amount of contributions to a particular MEPP could also be affected by the terms of the CBA, which could require at a particular time, an increase in the contribution rate and/or surcharges. Our contributions to various MEPPs increased by approximately $4.8 million as a result of acquisitions made by us since 2017. We also participated in an MEPP that is located within the United Kingdom for which we have contributed less than $0.1 million for each of the years ended December 31, 2019 , 2018 , and 2017 . The information that we have obtained relating to this plan is not as readily available and/or as comparable as the information that has been ascertained in the United States. Based upon the most recently available information, the plan is 100% funded. This plan closed to future contributions and participants during 2019. Additionally, we contribute to certain multiemployer plans that provide post retirement benefits such as health and welfare benefits and/or defined contribution/annuity plans, among others. Our contributions to these plans were approximately $153.5 million , $135.9 million , and $130.9 million for the years ended December 31, 2019 , 2018 , and 2017 , respectively. Our contributions to other post retirement benefit plans increased by approximately $11.0 million as a result of acquisitions made by us since 2017. The amount of contributions to these plans is also subject for the most part to the factors discussed above in conjunction with the MEPPs. Defined Contribution Plans We have defined contribution retirement and savings plans that cover eligible employees in the United States. Contributions to these plans are based on a percentage of the employee’s base compensation. The expenses recognized for the years ended December 31, 2019 , 2018 , and 2017 for these plans were approximately $32.4 million , $29.8 million , and $28.1 million , respectively. At our discretion and subject to applicable plan documents, we may make additional supplemental matching contributions to one of our defined contribution retirement and savings plans. The expenses recognized related to additional supplemental matching contributions for the years ended December 31, 2019 , 2018 , and 2017 were approximately $6.8 million , $6.1 million , and $5.5 million , respectively. Our United Kingdom subsidiary also has defined contribution retirement plans. The expense recognized for the years ended December 31, 2019 , 2018 , and 2017 was approximately $6.1 million , $4.9 million , and $3.9 million

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Contractual Guarantees We have agreements with our executive officers and certain other key management personnel providing for severance benefits for such employees upon termination of their employment under certain circumstances. In the ordinary course of business, we, at times, guarantee obligations of our subsidiaries under certain contracts. Generally, we are liable under such an arrangement only if our subsidiary fails to perform its obligations under the contract. Historically, we have not incurred any substantial liabilities as a consequence of these guarantees. The terms of our construction contracts frequently require that we obtain from surety companies (“Surety Companies”) and provide to our customers payment and performance bonds (“Surety Bonds”) as a condition to the award of such contracts. Surety Bonds are issued in return for premiums, which vary depending on the size and type of the bond, and secure our payment and performance obligations under such contracts. We have agreed to indemnify the Surety Companies for amounts, if any, paid by them in respect of Surety Bonds issued on our behalf. Public sector contracts require Surety Bonds more frequently than private sector contracts and, accordingly, our bonding requirements typically increase as the amount of our public sector work increases. In addition, at the request of labor unions representing certain of our employees, Surety Bonds are sometimes provided to secure obligations for wages and benefits payable to or for such employees. As of December 31, 2019 , based on the percentage-of-completion of our projects covered by Surety Bonds, our aggregate estimated exposure, assuming defaults on all our then existing contractual obligations, was approximately $1.2 billion . We are not aware of any losses in connection with Surety Bonds, which have been posted on our behalf, and we do not expect to incur significant losses in the foreseeable future. We are subject to regulation with respect to the handling of certain materials used in construction, which are classified as hazardous or toxic by federal, state, and local agencies. Our practice is to avoid participation in projects principally involving the remediation or removal of such materials. However, when remediation is required as part of our contract performance, we believe we comply with all applicable regulations governing the discharge of hazardous materials into the environment or otherwise relating to the protection of the environment. At December 31, 2019 , we employed approximately 36,000 people, approximately 59% of whom are represented by various unions pursuant to approximately 400 collective bargaining agreements between our individual subsidiaries and local unions. We believe that our employee relations are generally good. Only two of these collective bargaining agreements are national or regional in scope. Restructuring expenses, primarily related to employee severance obligations, were $1.5 million , $2.3 million , and $1.6 million for the years ended December 31, 2019 , 2018 , and 2017 , respectively. As of December 31, 2019 , 2018 , and 2017 , the balance of our restructuring related obligations yet to be paid was $1.6 million , $1.6 million , and $0.5 million , respectively. The majority of obligations outstanding as of December 31, 2018 and 2017 were paid during 2019 and 2018 , respectively. The obligations outstanding as of December 31, 2019 will be paid pursuant to our contractual obligations throughout 2020 and 2021. No material expenses in connection with restructuring from continuing operations are expected to be incurred during 2020. The changes in restructuring activity by reportable segment during the years ended December 31, 2019 and 2018 were as follows (in thousands): United States United States building services segment Corporate administration Total Balance at December 31, 2017 $ 452 $ 40 $ — $ 492 Charges — 882 1,424 2,306 Payments (422 ) (746 ) — (1,168 ) Balance at December 31, 2018 30 176 1,424 1,630 Charges 445 1,078 — 1,523 Payments (30 ) (842 ) (723 ) (1,595 ) Balance at December 31, 2019 $ 445 $ 412 $ 701 $ 1,558 Government Contracts As a government contractor, we are subject to U.S. government audits and investigations relating to our operations, fines, penalties and compensatory and treble damages, and possible suspension or debarment from doing business with the government. Based on currently available information, we believe the outcome of ongoing government disputes and investigations will not have a material impact on our financial position, results of operations or liquidity. Legal Matters We are involved in several legal proceedings in which damages and claims have been asserted against us. We believe that we have a number of valid defenses to such proceedings and claims and intend to vigorously defend ourselves. Other potential claims may exist that have not yet been asserted against us. We do not believe that any such matters will have a material adverse effect on our financial position, results of operations or liquidity. Litigation is subject to many uncertainties and the outcome of litigation is not predictable with assurance. It is possible that some litigation matters for which liabilities have not been recorded could be decided unfavorably to us, and that any such unfavorable decisions could have a material adverse effect on our financial position, results of operations or liquidity.

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Lessee, Operating Leases	Leases On January 1, 2019, we adopted Accounting Standards Codification Topic 842, “Leases” (“ASC 842”). This pronouncement requires lessees to record right-of-use assets and corresponding lease liabilities on the balance sheet for most leases. We adopted this pronouncement utilizing the transition practical expedient which eliminates the requirement that the new lease standard be applied to comparative periods presented in the year of adoption. As part of our adoption, we elected to utilize the package of practical expedients permitted under the new standard, which allowed us to not reassess: (a) whether an existing contract is or contains a lease, (b) the classification for existing leases, and (c) initial direct costs. Further, as permitted by the standard, we made an accounting policy election not to record right-of-use assets or lease liabilities for leases with an initial term of 12 months or less. Instead, consistent with previous accounting guidance, we will recognize payments for such leases in the statement of operations on a straight-line basis over the lease term. We lease real estate, vehicles and equipment under various arrangements which are classified as either operating or finance leases. A lease exists when a contract or part of a contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration. In determining whether a lease exists, we consider whether a contract provides us with both: (a) the right to obtain substantially all of the economic benefits from the use of the identified asset and (b) the right to direct the use of the identified asset. Many of our leases include base rental periods coupled with options to renew or terminate the lease, generally at our discretion. Certain leases additionally include options to purchase the leased asset. In evaluating the lease term, we consider whether we are reasonably certain to exercise such options. To the extent a significant economic incentive exists to exercise an option, that option is included within the lease term. However, based on the nature of our lease arrangements, options generally do not provide us with a significant economic incentive and are therefore excluded from the lease term for the majority of our arrangements. Our leases typically include a combination of fixed and variable payments. Fixed payments are generally included when measuring the right-of-use asset and lease liability. Variable payments, which primarily represent payments based on usage of the underlying asset, are generally excluded from such measurement and expensed as incurred. In addition, certain of our lease arrangements may contain a lease coupled with an arrangement to provide other services, such as maintenance, or may require us to make other payments on behalf of the lessor related to the leased asset, such as payments for taxes or insurance. As permitted by ASC 842, we have elected to account for these non-lease components together with the associated lease component. This election has been made for each of our asset classes. The measurement of right-of-use assets and lease liabilities requires us to estimate appropriate discount rates. To the extent the rate implicit in the lease is readily determinable, such rate is utilized. However, based on information available at lease commencement for the majority of our leases, the rate implicit in the lease is not known. In these instances, we utilize an incremental borrowing rate, which represents the rate of interest that we would pay to borrow on a collateralized basis over a similar term. Our lease arrangements generally do not contain significant restrictions or covenants; however, certain of our vehicle and equipment leases include residual value guarantees, whereby we provide a guarantee to the lessor that the value of the underlying asset will be at least a specified amount at the end of the lease. Amounts probable of being owed under these guarantees are included within the measurement of the right-of-use asset and lease liability. Lease Position as of December 31, 2019 The following table presents the lease-related assets and liabilities reported in the Consolidated Balance Sheet as of December 31, 2019 (in thousands): Classification on the Consolidated Balance Sheet December 31, Assets Operating lease assets Operating lease right-of-use assets $ 245,471 Finance lease assets Property, plant and equipment, net 9,609 Total lease assets $ 255,080 Liabilities Current Operating Operating lease liabilities, current $ 53,144 Finance Current maturities of long-term debt and finance lease liabilities 4,088 Noncurrent Operating Operating lease liabilities, long-term 204,950 Finance Long-term debt and finance lease liabilities 5,591 Total lease liabilities $ 267,773 Lease Costs The following table presents information related to lease expense for the year ended December 31, 2019 (in thousands): 2019 Finance lease expense: Amortization expense $ 4,575 Interest expense 427 Operating lease expense 66,650 Short-term lease expense 149,528 Variable lease expense 4,924 Total lease expense $ 226,104 Rent expense for operating leases and other rental items, including short-term equipment rentals, for the years ended December 31, 2018 and 2017 was approximately $191.8 million and $166.5 million , respectively. For the years ended December 31, 2019 , 2018 , and 2017 , sublease rental income was approximately $0.5 million , $0.6 million , and $0.6 million , respectively. Lease Term and Discount Rate The following table presents certain information related to lease terms and discount rates for leases as of December 31, 2019 : December 31, Weighted-average remaining lease term: Operating leases 6.7 years Finance leases 2.9 years Weighed-average discount rate: Operating leases 4.04 % Finance leases 4.16 % Other Information The following table presents supplemental cash flow information related to leases for the year ended December 31, 2019 (in thousands): 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows used for operating leases $ 65,757 Operating cash flows used for finance leases $ 427 Financing cash flows used for finance leases $ 4,571 Right-of-use assets obtained in exchange for new operating lease liabilities $ 84,089 Right-of-use assets obtained in exchange for new finance lease liabilities $ 5,311 For the years ended December 31, 2018 and 2017 (prior to the adoption of ASC 842), assets acquired under capital leases amounted to approximately $1.1 million and $1.3 million , respectively. Maturity of Lease Liabilities The following table reconciles future minimum lease payments on an undiscounted cash flow basis to the lease liabilities reported in the Consolidated Balance Sheet as of December 31, 2019 (in thousands): Operating Leases Finance Leases 2020 $ 62,457 $ 4,391 2021 50,505 3,039 2022 42,155 1,807 2023 35,223 743 2024 26,049 138 Thereafter 80,661 129 Total minimum lease payments 297,050 10,247 Less: Amount of lease payments representing interest (38,956 ) (568 ) Present value of future minimum lease payments $ 258,094 $ 9,679 Current portion of lease liabilities $ 53,144 $ 4,088 Noncurrent portion of lease liabilities 204,950 5,591 Present value of future minimum lease payments $ 258,094 $ 9,679
Leasee, Finance Leases	Leases On January 1, 2019, we adopted Accounting Standards Codification Topic 842, “Leases” (“ASC 842”). This pronouncement requires lessees to record right-of-use assets and corresponding lease liabilities on the balance sheet for most leases. We adopted this pronouncement utilizing the transition practical expedient which eliminates the requirement that the new lease standard be applied to comparative periods presented in the year of adoption. As part of our adoption, we elected to utilize the package of practical expedients permitted under the new standard, which allowed us to not reassess: (a) whether an existing contract is or contains a lease, (b) the classification for existing leases, and (c) initial direct costs. Further, as permitted by the standard, we made an accounting policy election not to record right-of-use assets or lease liabilities for leases with an initial term of 12 months or less. Instead, consistent with previous accounting guidance, we will recognize payments for such leases in the statement of operations on a straight-line basis over the lease term. We lease real estate, vehicles and equipment under various arrangements which are classified as either operating or finance leases. A lease exists when a contract or part of a contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration. In determining whether a lease exists, we consider whether a contract provides us with both: (a) the right to obtain substantially all of the economic benefits from the use of the identified asset and (b) the right to direct the use of the identified asset. Many of our leases include base rental periods coupled with options to renew or terminate the lease, generally at our discretion. Certain leases additionally include options to purchase the leased asset. In evaluating the lease term, we consider whether we are reasonably certain to exercise such options. To the extent a significant economic incentive exists to exercise an option, that option is included within the lease term. However, based on the nature of our lease arrangements, options generally do not provide us with a significant economic incentive and are therefore excluded from the lease term for the majority of our arrangements. Our leases typically include a combination of fixed and variable payments. Fixed payments are generally included when measuring the right-of-use asset and lease liability. Variable payments, which primarily represent payments based on usage of the underlying asset, are generally excluded from such measurement and expensed as incurred. In addition, certain of our lease arrangements may contain a lease coupled with an arrangement to provide other services, such as maintenance, or may require us to make other payments on behalf of the lessor related to the leased asset, such as payments for taxes or insurance. As permitted by ASC 842, we have elected to account for these non-lease components together with the associated lease component. This election has been made for each of our asset classes. The measurement of right-of-use assets and lease liabilities requires us to estimate appropriate discount rates. To the extent the rate implicit in the lease is readily determinable, such rate is utilized. However, based on information available at lease commencement for the majority of our leases, the rate implicit in the lease is not known. In these instances, we utilize an incremental borrowing rate, which represents the rate of interest that we would pay to borrow on a collateralized basis over a similar term. Our lease arrangements generally do not contain significant restrictions or covenants; however, certain of our vehicle and equipment leases include residual value guarantees, whereby we provide a guarantee to the lessor that the value of the underlying asset will be at least a specified amount at the end of the lease. Amounts probable of being owed under these guarantees are included within the measurement of the right-of-use asset and lease liability. Lease Position as of December 31, 2019 The following table presents the lease-related assets and liabilities reported in the Consolidated Balance Sheet as of December 31, 2019 (in thousands): Classification on the Consolidated Balance Sheet December 31, Assets Operating lease assets Operating lease right-of-use assets $ 245,471 Finance lease assets Property, plant and equipment, net 9,609 Total lease assets $ 255,080 Liabilities Current Operating Operating lease liabilities, current $ 53,144 Finance Current maturities of long-term debt and finance lease liabilities 4,088 Noncurrent Operating Operating lease liabilities, long-term 204,950 Finance Long-term debt and finance lease liabilities 5,591 Total lease liabilities $ 267,773 Lease Costs The following table presents information related to lease expense for the year ended December 31, 2019 (in thousands): 2019 Finance lease expense: Amortization expense $ 4,575 Interest expense 427 Operating lease expense 66,650 Short-term lease expense 149,528 Variable lease expense 4,924 Total lease expense $ 226,104 Rent expense for operating leases and other rental items, including short-term equipment rentals, for the years ended December 31, 2018 and 2017 was approximately $191.8 million and $166.5 million , respectively. For the years ended December 31, 2019 , 2018 , and 2017 , sublease rental income was approximately $0.5 million , $0.6 million , and $0.6 million , respectively. Lease Term and Discount Rate The following table presents certain information related to lease terms and discount rates for leases as of December 31, 2019 : December 31, Weighted-average remaining lease term: Operating leases 6.7 years Finance leases 2.9 years Weighed-average discount rate: Operating leases 4.04 % Finance leases 4.16 % Other Information The following table presents supplemental cash flow information related to leases for the year ended December 31, 2019 (in thousands): 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows used for operating leases $ 65,757 Operating cash flows used for finance leases $ 427 Financing cash flows used for finance leases $ 4,571 Right-of-use assets obtained in exchange for new operating lease liabilities $ 84,089 Right-of-use assets obtained in exchange for new finance lease liabilities $ 5,311 For the years ended December 31, 2018 and 2017 (prior to the adoption of ASC 842), assets acquired under capital leases amounted to approximately $1.1 million and $1.3 million , respectively. Maturity of Lease Liabilities The following table reconciles future minimum lease payments on an undiscounted cash flow basis to the lease liabilities reported in the Consolidated Balance Sheet as of December 31, 2019 (in thousands): Operating Leases Finance Leases 2020 $ 62,457 $ 4,391 2021 50,505 3,039 2022 42,155 1,807 2023 35,223 743 2024 26,049 138 Thereafter 80,661 129 Total minimum lease payments 297,050 10,247 Less: Amount of lease payments representing interest (38,956 ) (568 ) Present value of future minimum lease payments $ 258,094 $ 9,679 Current portion of lease liabilities $ 53,144 $ 4,088 Noncurrent portion of lease liabilities 204,950 5,591 Present value of future minimum lease payments $ 258,094 $ 9,679

Additional Cash Flow Informatio

Additional Cash Flow Information	12 Months Ended
	Dec. 31, 2019
Supplemental Cash Flow Information [Abstract]
Additional Cash Flow Information	ADDITIONAL CASH FLOW INFORMATION The following presents information about cash paid for interest and income taxes for the years ended December 31, 2019 , 2018 , and 2017 (in thousands): 2019 2018 2017 Cash paid during the year for: Interest $ 12,683 $ 12,435 $ 11,456 Income taxes $ 126,169 $ 123,651 $ 130,226

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Segment Information	SEGMENT INFORMATION Our reportable segments reflect certain reclassifications of prior year amounts from our United States mechanical construction and facilities services segment to our United States building services and our United States industrial services segments due to changes in our internal reporting structure. We have the following reportable segments: (a) United States electrical construction and facilities services (involving systems for electrical power transmission and distribution; premises electrical and lighting systems; process instrumentation in the refining, chemical processing, food processing and mining industries; low-voltage systems, such as fire alarm, security and process control; voice and data communication; roadway and transit lighting; and fiber optic lines); (b) United States mechanical construction and facilities services (involving systems for heating, ventilation, air conditioning, refrigeration and clean-room process ventilation; fire protection; plumbing, process and high-purity piping; controls and filtration; water and wastewater treatment and central plant heating and cooling; cranes and rigging; millwrighting; and steel fabrication, erection and welding); (c) United States building services; (d) United States industrial services; and (e) United Kingdom building services. The “United States building services” and “United Kingdom building services” segments principally consist of those operations which provide a portfolio of services needed to support the operation and maintenance of customers’ facilities, including commercial and government site-based operations and maintenance; facility maintenance and services, including reception, security and catering services; outage services to utilities and industrial plants; military base operations support services; mobile mechanical maintenance and services; floor care and janitorial services; landscaping, lot sweeping and snow removal; facilities management; vendor management; call center services; installation and support for building systems; program development, management and maintenance for energy systems; technical consulting and diagnostic services; infrastructure and building projects for federal, state and local governmental agencies and bodies; and small modification and retrofit projects, which services are not generally related to customers’ construction programs. The “United States industrial services” segment principally consists of those operations which provide industrial maintenance and services for refineries, petrochemical plants, and other customers within the oil and gas industry. Services of this segment include refinery turnaround planning and engineering; specialty welding; overhaul and maintenance of critical process units; specialty technical services; on-site repairs, maintenance and service of heat exchangers, towers, vessels and piping; design, manufacturing, repair, and hydro blast cleaning of shell and tube heat exchangers and related equipment; and construction, maintenance, and other support services for customers within the upstream and midstream sectors. The following tables present information about industry segments and geographic areas for the years ended December 31, 2019 , 2018 , and 2017 (in thousands): 2019 2018 2017 Revenues from unrelated entities: United States electrical construction and facilities services $ 2,216,600 $ 1,954,323 $ 1,829,567 United States mechanical construction and facilities services 3,340,337 2,962,843 2,880,148 United States building services 2,106,872 1,875,485 1,753,703 United States industrial services 1,087,543 923,109 882,836 Total United States operations 8,751,352 7,715,760 7,346,254 United Kingdom building services 423,259 414,871 340,745 Total worldwide operations $ 9,174,611 $ 8,130,631 $ 7,686,999 Total revenues: United States electrical construction and facilities services $ 2,220,582 $ 1,959,978 $ 1,836,985 United States mechanical construction and facilities services 3,370,960 2,998,918 2,911,033 United States building services 2,182,390 1,942,663 1,812,763 United States industrial services 1,111,264 930,724 885,198 Less intersegment revenues (133,844 ) (116,523 ) (99,725 ) Total United States operations 8,751,352 7,715,760 7,346,254 United Kingdom building services 423,259 414,871 340,745 Total worldwide operations $ 9,174,611 $ 8,130,631 $ 7,686,999 2019 2018 2017 Operating income (loss): United States electrical construction and facilities services $ 161,684 $ 139,430 $ 150,001 United States mechanical construction and facilities services 225,040 219,853 192,167 United States building services 114,754 93,827 81,720 United States industrial services 44,340 27,671 39,313 Total United States operations 545,818 480,781 463,201 United Kingdom building services 18,323 15,930 12,905 Corporate administration (101,726 ) (90,415 ) (87,808 ) Restructuring expenses (1,523 ) (2,306 ) (1,577 ) Impairment loss on goodwill and identifiable intangible assets — (907 ) (57,819 ) Total worldwide operations 460,892 403,083 328,902 Other corporate items: Net periodic pension (cost) income 1,553 2,743 1,652 Interest expense (13,821 ) (13,544 ) (12,770 ) Interest income 2,265 2,746 965 Income from continuing operations before income taxes $ 450,889 $ 395,028 $ 318,749 Capital expenditures: United States electrical construction and facilities services $ 5,876 $ 5,993 $ 4,797 United States mechanical construction and facilities services 7,890 7,504 6,665 United States building services 14,291 10,414 10,745 United States industrial services 15,802 18,386 9,696 Total United States operations 43,859 42,297 31,903 United Kingdom building services 3,598 870 2,166 Corporate administration 975 312 615 Total worldwide operations $ 48,432 $ 43,479 $ 34,684 Depreciation and amortization of property, plant and equipment: United States electrical construction and facilities services $ 7,550 $ 6,221 $ 6,545 United States mechanical construction and facilities services 8,764 7,803 7,504 United States building services 12,728 10,324 11,051 United States industrial services 11,154 9,943 10,589 Total United States operations 40,196 34,291 35,689 United Kingdom building services 2,942 3,447 3,371 Corporate administration 807 734 855 Total worldwide operations $ 43,945 $ 38,472 $ 39,915 2019 2018 2017 Contract assets: United States electrical construction and facilities services $ 50,813 $ 38,412 $ 35,060 United States mechanical construction and facilities services 61,225 49,302 50,302 United States building services 30,428 33,304 26,028 United States industrial services 9,820 14,117 3,715 Total United States operations 152,286 135,135 115,105 United Kingdom building services 25,544 23,108 7,516 Total worldwide operations $ 177,830 $ 158,243 $ 122,621 Contract liabilities: United States electrical construction and facilities services $ 173,967 $ 163,951 $ 178,454 United States mechanical construction and facilities services 317,083 280,846 288,699 United States building services 97,588 79,281 48,481 United States industrial services 12,404 12,307 4,615 Total United States operations 601,042 536,385 520,249 United Kingdom building services 22,600 15,905 3,907 Total worldwide operations $ 623,642 $ 552,290 $ 524,156 Long-lived assets: United States electrical construction and facilities services $ 215,780 $ 201,333 $ 180,990 United States mechanical construction and facilities services 530,561 334,628 340,030 United States building services 458,915 436,887 409,718 United States industrial services 615,233 630,340 643,124 Total United States operations 1,820,489 1,603,188 1,573,862 United Kingdom building services 9,622 9,264 11,729 Corporate administration 1,431 1,072 1,494 Total worldwide operations $ 1,831,542 $ 1,613,524 $ 1,587,085 Total assets: United States electrical construction and facilities services $ 834,802 $ 702,112 $ 617,471 United States mechanical construction and facilities services 1,536,325 1,081,005 1,071,164 United States building services 996,664 846,221 764,085 United States industrial services 829,793 864,446 798,975 Total United States operations 4,197,584 3,493,784 3,251,695 United Kingdom building services 181,147 146,379 131,806 Corporate administration 451,627 448,644 582,403 Total worldwide operations $ 4,830,358 $ 4,088,807 $ 3,965,904 During 2018, we recognized losses of $10.0 million on a transportation project within our United States electrical construction and facilities services segment, resulting in part from contract scope issues. During 2017, we recognized $18.1 million

Selected Unaudited Quarterly In

Selected Unaudited Quarterly Information	12 Months Ended
	Dec. 31, 2019
Selected Quarterly Financial Information [Abstract]
Selected Unaudited Quarterly Information	SELECTED UNAUDITED QUARTERLY INFORMATION (In thousands, except per share data) Quarterly and year-to-date computations of per share amounts are made independently; therefore, the sum of per share amounts for the quarters may not equal per share amounts for the year. The results of the construction operations of our United Kingdom segment for all periods are presented as discontinued operations. March 31 June 30 Sept. 30 Dec. 31 2019 Quarterly Results Revenues $ 2,158,728 $ 2,324,202 $ 2,287,741 $ 2,403,940 Gross profit $ 308,754 $ 346,380 $ 335,987 $ 364,747 Net income attributable to EMCOR Group, Inc. $ 72,410 $ 83,972 $ 81,834 $ 86,924 Basic EPS from continuing operations $ 1.29 $ 1.49 $ 1.46 $ 1.54 Basic EPS from discontinued operation — — — — $ 1.29 $ 1.49 $ 1.46 $ 1.54 Diluted EPS from continuing operations $ 1.28 $ 1.49 $ 1.45 $ 1.54 Diluted EPS from discontinued operation — — — — $ 1.28 $ 1.49 $ 1.45 $ 1.54 March 31 June 30 Sept. 30 Dec. 31 2018 Quarterly Results Revenues $ 1,900,388 $ 1,953,886 $ 2,047,049 $ 2,229,308 Gross profit $ 269,119 $ 290,844 $ 309,339 $ 336,151 Impairment loss on identifiable intangible assets $ — $ 907 $ — $ — Net income attributable to EMCOR Group, Inc. $ 55,374 $ 70,816 $ 79,373 $ 77,968 Basic EPS from continuing operations $ 0.95 $ 1.22 $ 1.37 $ 1.39 Basic EPS from discontinued operation (0.00 ) (0.00 ) (0.01 ) (0.02 ) $ 0.95 $ 1.22 $ 1.36 $ 1.37 Diluted EPS from continuing operations $ 0.94 $ 1.21 $ 1.36 $ 1.38 Diluted EPS from discontinued operation (0.00 ) (0.00 ) (0.01 ) (0.02 ) $ 0.94 $ 1.21 $ 1.35 $ 1.36

Subsequent Event Subsequent Eve

Subsequent Event Subsequent Event	12 Months Ended
	Dec. 31, 2019
Subsequent Event [Abstract]
Subsequent Event	SUBSEQUENT EVENTS In January 2020, we acquired a company for an immaterial amount. This company provides mobile mechanical services within the Northeastern region of the United States, and its results will be included in our United States building services segment. The acquisition of this business will be accounted for by the acquisition method, and the amount paid will be allocated to its respective assets and liabilities, based upon the estimated fair value of such assets and liabilities at the date of acquisition by us.

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2019
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule of Valuation and Qualifying Accounts Disclosure	Description Balance at Beginning of Year Costs and Expenses Deductions (1) Balance at End of Year Allowance for doubtful accounts Year Ended December 31, 2019 $ 15,361 2,628 (3,523 ) $ 14,466 Year Ended December 31, 2018 $ 17,230 2,123 (3,992 ) $ 15,361 Year Ended December 31, 2017 $ 12,252 7,264 (2,286 ) $ 17,230 _________________ (1)

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Fair Value Measurements	We use a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy, which gives the highest priority to quoted prices in active markets, is comprised of the following three levels: Level 1 – Unadjusted quoted market prices in active markets for identical assets and liabilities. Level 2 – Observable inputs, other than Level 1 inputs. Level 2 inputs would typically include quoted prices in markets that are not active or financial instruments for which all significant inputs are observable, either directly or indirectly. Level 3 – Prices or valuations that require inputs that are both significant to the measurement and unobservable.
Leases	On January 1, 2019, we adopted Accounting Standards Codification Topic 842, “Leases” (“ASC 842”). This pronouncement requires lessees to record right-of-use assets and corresponding lease liabilities on the balance sheet for most leases. We adopted this pronouncement utilizing the transition practical expedient which eliminates the requirement that the new lease standard be applied to comparative periods presented in the year of adoption. As part of our adoption, we elected to utilize the package of practical expedients permitted under the new standard, which allowed us to not reassess: (a) whether an existing contract is or contains a lease, (b) the classification for existing leases, and (c) initial direct costs. Further, as permitted by the standard, we made an accounting policy election not to record right-of-use assets or lease liabilities for leases with an initial term of 12 months or less. Instead, consistent with previous accounting guidance, we will recognize payments for such leases in the statement of operations on a straight-line basis over the lease term. We lease real estate, vehicles and equipment under various arrangements which are classified as either operating or finance leases. A lease exists when a contract or part of a contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration. In determining whether a lease exists, we consider whether a contract provides us with both: (a) the right to obtain substantially all of the economic benefits from the use of the identified asset and (b) the right to direct the use of the identified asset. Many of our leases include base rental periods coupled with options to renew or terminate the lease, generally at our discretion. Certain leases additionally include options to purchase the leased asset. In evaluating the lease term, we consider whether we are reasonably certain to exercise such options. To the extent a significant economic incentive exists to exercise an option, that option is included within the lease term. However, based on the nature of our lease arrangements, options generally do not provide us with a significant economic incentive and are therefore excluded from the lease term for the majority of our arrangements. Our leases typically include a combination of fixed and variable payments. Fixed payments are generally included when measuring the right-of-use asset and lease liability. Variable payments, which primarily represent payments based on usage of the underlying asset, are generally excluded from such measurement and expensed as incurred. In addition, certain of our lease arrangements may contain a lease coupled with an arrangement to provide other services, such as maintenance, or may require us to make other payments on behalf of the lessor related to the leased asset, such as payments for taxes or insurance. As permitted by ASC 842, we have elected to account for these non-lease components together with the associated lease component. This election has been made for each of our asset classes. The measurement of right-of-use assets and lease liabilities requires us to estimate appropriate discount rates. To the extent the rate implicit in the lease is readily determinable, such rate is utilized. However, based on information available at lease commencement for the majority of our leases, the rate implicit in the lease is not known. In these instances, we utilize an incremental borrowing rate, which represents the rate of interest that we would pay to borrow on a collateralized basis over a similar term.
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of the Company and its majority-owned subsidiaries and joint ventures. Significant intercompany accounts and transactions have been eliminated. All investments over which we exercise significant influence, but do not control (a 20% to 50% ownership interest), are accounted for using the equity method of accounting. For joint ventures that have been accounted for using the consolidation method of accounting, noncontrolling interests represent the allocation of earnings to our joint venture partners who either have a minority-ownership interest in the joint venture or are not at risk for the majority of losses of the joint venture. The results of operations of companies acquired have been included in the results of operations from the date of the respective acquisition.
Principles of Preparation	Principles of Preparation The preparation of the consolidated financial statements, in conformity with accounting principles generally accepted in the United States, requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could materially differ from those estimates.
Revenue Recognition	Revenue Recognition The Company adopted Accounting Standards Codification Topic 606, “Revenue from Contracts with Customers” (“ASC 606”) on January 1, 2018. In accordance with ASC 606, revenue is recognized when promised goods or services are transferred to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those goods or services. Refer to Note 3 - Revenue from Contracts with Customers of the notes to consolidated financial statements for additional information. The Company recognizes revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those goods or services by applying the following five step model: (1) Identify the contract with a customer A contract with a customer exists when: (a) the parties have approved the contract and are committed to perform their respective obligations, (b) the rights of the parties can be identified, (c) payment terms can be identified, (d) the arrangement has commercial substance, and (e) collectibility of consideration is probable. Judgment is required when determining if the contractual criteria are met, specifically in the earlier stages of a project when a formally executed contract may not yet exist. In these situations, the Company evaluates all relevant facts and circumstances, including the existence of other forms of documentation or historical experience with our customers that may indicate a contractual agreement is in place and revenue should be recognized. In determining if the collectibility of consideration is probable, the Company considers the customer’s ability and intention to pay such consideration through an evaluation of several factors, including an assessment of the creditworthiness of the customer and our prior collection history with such customer. (2) Identify the performance obligations in the contract At contract inception, the Company assesses the goods or services promised in a contract and identifies, as a separate performance obligation, each distinct promise to transfer goods or services to the customer. The identified performance obligations represent the “unit of account” for purposes of determining revenue recognition. In order to properly identify separate performance obligations, the Company applies judgment in determining whether each good or service provided is: (a) capable of being distinct, whereby the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer, and (b) distinct within the context of the contract, whereby the transfer of the good or service to the customer is separately identifiable from other promises in the contract. In addition, when assessing performance obligations within a contract, the Company considers the warranty provisions included within such contract. To the extent the warranty terms provide the customer with an additional service, other than assurance that the promised good or service complies with agreed upon specifications, such warranty is accounted for as a separate performance obligation. In determining whether a warranty provides an additional service, the Company considers each warranty provision in comparison to warranty terms which are standard in the industry. Our contracts are often modified through change orders to account for changes in the scope and price of the goods or services we are providing. Although the Company evaluates each change order to determine whether such modification creates a separate performance obligation, the majority of our change orders are for goods or services that are not distinct within the context of our original contract, and therefore, are not treated as separate performance obligations. (3) Determine the transaction price The transaction price represents the amount of consideration to which the Company expects to be entitled in exchange for transferring promised goods or services to our customers. The consideration promised within a contract may include fixed amounts, variable amounts, or both. To the extent the performance obligation includes variable consideration, including contract bonuses and penalties that can either increase or decrease the transaction price, the Company estimates the amount of variable consideration to be included in the transaction price utilizing one of two prescribed methods, depending on which method better predicts the amount of consideration to which the entity will be entitled. Such methods include: (a) the expected value method, whereby the amount of variable consideration to be recognized represents the sum of probability weighted amounts in a range of possible consideration amounts, and (b) the most likely amount method, whereby the amount of variable consideration to be recognized represents the single most likely amount in a range of possible consideration amounts. When applying these methods, the Company considers all information that is reasonably available, including historical, current, and estimates of future performance. The expected value method is typically utilized in situations where a contract contains a large number of possible outcomes while the most likely amount method is typically utilized in situations where a contract has only two possible outcomes. Variable consideration is included in the transaction price only to the extent it is probable, in the Company’s judgment, that a significant future reversal in the amount of cumulative revenue recognized under the contract will not occur when the uncertainty associated with the variable consideration is subsequently resolved. This threshold is referred to as the variable consideration constraint. In assessing whether to apply the variable consideration constraint, the Company considers if factors exist that could increase the likelihood or the magnitude of a potential reversal of revenue, including, but not limited to, whether: (a) the amount of consideration is highly susceptible to factors outside of the Company’s influence, such as the actions of third parties, (b) the uncertainty surrounding the amount of consideration is not expected to be resolved for a long period of time, (c) the Company’s experience with similar types of contracts is limited or that experience has limited predictive value, (d) the Company has a practice of either offering a broad range of price concessions or changing the payment terms and conditions of similar contracts in similar circumstances, and (e) the contract has a large number and broad range of possible consideration amounts. Pending change orders represent one of the most common forms of variable consideration included within contract value and typically represent contract modifications for which a change in scope has been authorized or acknowledged by our customer, but the final adjustment to contract price is yet to be negotiated. In estimating the transaction price for pending change orders, the Company considers all relevant facts, including documented correspondence with the customer regarding acknowledgment of and/or agreement with the modification, as well as historical experience with the customer or similar contractual circumstances. Based upon this assessment, the Company estimates the transaction price, including whether the variable consideration constraint should be applied. Contract claims are another form of variable consideration which is common within our industry. Claim amounts represent revenue that has been recognized for contract modifications that are not submitted or are in dispute as to both scope and price. In estimating the transaction price for claims, the Company considers all relevant facts available. However, given the uncertainty surrounding claims, including the potential long-term nature of dispute resolution and the broad range of possible consideration amounts, there is an increased likelihood that any additional contract revenue associated with contract claims is constrained. The resolution of claims involves negotiations and, in certain cases, litigation. In the event litigation costs are incurred by us in connection with claims, such litigation costs are expensed as incurred, although we may seek to recover these costs. For some transactions, the receipt of consideration does not match the timing of the transfer of goods or services to the customer. For such contracts, the Company evaluates whether this timing difference represents a financing arrangement within the contract. Although rare, if a contract is determined to contain a significant financing component, the Company adjusts the promised amount of consideration for the effects of the time value of money when determining the transaction price of such contract. Although our customers may retain a portion of the contract price until completion of the project and final contract settlement, these retainage amounts are not considered a significant financing component as the intent of the withheld amounts is to provide the customer with assurance that we will complete our obligations under the contract rather than to provide financing to the customer. In addition, although we may be entitled to advanced payments from our customers on certain contracts, these advanced payments generally do not represent a significant financing component as the payments are used to meet working capital demands that can be higher in the early stages of a contract, as well as to protect us from our customer failing to meet its obligations under the contract. Changes in the estimates of transaction prices are recognized on a cumulative catch-up basis in the period in which the revisions to the estimates are made. Such changes in estimates can result in the recognition of revenue in a current period for performance obligations which were satisfied or partially satisfied in prior periods. Such changes in estimates may also result in the reversal of previously recognized revenue if the ultimate outcome differs from the Company’s previous estimate. There were no significant amounts of revenue recognized during the year ended December 31, 2019 related to performance obligations satisfied in prior periods. For the year ended December 31, 2018 , we recognized revenue of $7.3 million associated with the final settlement of contract value for three projects which were completed in prior periods. For the years ended December 31, 2019 and 2018 , there were no significant reversals of revenue recognized associated with the revision of transaction prices. (4) Allocate the transaction price to performance obligations in the contract For contracts that contain multiple performance obligations, the Company allocates the transaction price to each performance obligation based on a relative standalone selling price. The Company determines the standalone selling price based on the price at which the performance obligation would have been sold separately in similar circumstances to similar customers. If the standalone selling price is not observable, the Company estimates the standalone selling price taking into account all available information such as market conditions and internal pricing guidelines. In certain circumstances, the standalone selling price is determined using an expected profit margin on anticipated costs related to the performance obligation. (5) Recognize revenue as performance obligations are satisfied The Company recognizes revenue at the time the related performance obligation is satisfied by transferring a promised good or service to its customers. A good or service is considered to be transferred when the customer obtains control. The Company can transfer control of a good or service and satisfy its performance obligations either over time or at a point in time. The Company transfers control of a good or service over time and, therefore, satisfies a performance obligation and recognizes revenue over time if one of the following three criteria are met: (a) the customer simultaneously receives and consumes the benefits provided by the Company’s performance as we perform, (b) the Company’s performance creates or enhances an asset that the customer controls as the asset is created or enhanced, or (c) the Company’s performance does not create an asset with an alternative use to us, and we have an enforceable right to payment for performance completed to date. For our performance obligations satisfied over time, we recognize revenue by measuring the progress toward complete satisfaction of that performance obligation. The selection of the method to measure progress towards completion can be either an input method or an output method and requires judgment based on the nature of the goods or services to be provided. For our construction contracts, revenue is generally recognized over time as our performance creates or enhances an asset that the customer controls as it is created or enhanced. Our fixed price construction projects generally use a cost-to-cost input method to measure our progress towards complete satisfaction of the performance obligation as we believe it best depicts the transfer of control to the customer which occurs as we incur costs on our contracts. Under the cost-to-cost measure of progress, the extent of progress towards completion is measured based on the ratio of costs incurred to date to the total estimated costs at completion of the performance obligation. For our unit price construction contracts, progress towards complete satisfaction is measured through an output method, such as the amount of units produced or delivered, when our performance does not produce significant amounts of work in process or finished goods prior to complete satisfaction of such performance obligations. For our services contracts, revenue is also generally recognized over time as the customer simultaneously receives and consumes the benefits of our performance as we perform the service. For our fixed price service contracts with specified service periods, revenue is generally recognized on a straight-line basis over such service period when our inputs are expended evenly, and the customer receives and consumes the benefits of our performance throughout the contract term. The timing of revenue recognition for the manufacturing of new build heat exchangers within our United States industrial services segment depends on the payment terms of the contract, as our performance does not create an asset with an alternative use to us. For those contracts for which we have a right to payment for performance completed to date at all times throughout our performance, inclusive of a cancellation, we recognize revenue over time. For these performance obligations, we use a cost-to-cost input method to measure our progress towards complete satisfaction of the performance obligation as we believe it best depicts the transfer of control to the customer which occurs as we incur costs on our contracts. However, for those contracts for which we do not have a right, at all times, to payment for performance completed to date, we recognize revenue at the point in time when control is transferred to the customer. For bill-and-hold arrangements, revenue is recognized when the customer obtains control of the heat exchanger, which may be prior to shipping, if certain recognition criteria are met. For certain of our revenue streams, such as call-out repair and service work, outage services, refinery turnarounds, and specialty welding services that are performed under time and materials contracts, our progress towards complete satisfaction of such performance obligations is measured using an output method as the customer receives and consumes the benefits of our performance completed to date. Due to uncertainties inherent in the estimation process, it is possible that estimates of costs to complete a performance obligation will be revised in the near-term. For those performance obligations for which revenue is recognized using a cost-to-cost input method, changes in total estimated costs, and related progress towards complete satisfaction of the performance obligation, are recognized on a cumulative catch-up basis in the period in which the revisions to the estimates are made. When the current estimate
Cash and cash equivalents	Cash and cash equivalents For purposes of the consolidated financial statements, we consider all highly liquid instruments with original maturities of three months or less to be cash equivalents. We maintain a centralized cash management system whereby our excess cash balances are invested in high quality, short-term money market instruments, which are considered cash equivalents. We have cash balances in certain of our domestic bank accounts that exceed federally insured limits.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts
Inventories	Inventories Inventories are stated at the lower of cost or net realizable value. Cost is determined principally using the average cost method.
Property, plant and equipment	Property, plant and equipment Property, plant and equipment is stated at cost. Depreciation, including amortization of assets under finance leases, is recorded principally using the straight-line method over estimated useful lives of 3 to 10 years for machinery and equipment, 3 to 7 years for vehicles, furniture and fixtures and computer hardware/software, and 25 years for buildings. Leasehold improvements are amortized over the shorter of the remaining life of the lease term or the expected useful life of the improvement.
Goodwill and Identifiable Intangible Assets	Goodwill and Identifiable Intangible Assets Goodwill and other identifiable intangible assets with indefinite lives that are not being amortized, such as trade names, are tested at least annually for impairment (which we test each October 1, absent any earlier identified impairment indicators) and are written down if impaired. Identifiable intangible assets with finite lives are amortized over their useful lives and are reviewed for impairment whenever facts and circumstances indicate that their carrying values may not be fully recoverable. See Note 9 - Goodwill and Identifiable Intangible Assets of the notes to consolidated financial statements for additional information.
Insurance Liabilities	Insurance Liabilities
Foreign Operations	Foreign Operations The financial statements and transactions of our foreign subsidiaries are maintained in their functional currency and translated into U.S. dollars in accordance with Accounting Standards Codification Topic 830, “Foreign Currency Matters.” Translation adjustments have been recorded as “Accumulated other comprehensive loss,” a separate component of “Equity.”
Income Taxes	Income Taxes We account for income taxes in accordance with the provisions of Accounting Standards Codification Topic 740, “Income Taxes” (“ASC 740”). ASC 740 requires an asset and liability approach which requires the recognition of deferred income tax assets and deferred income tax liabilities for the expected future tax consequences of temporary differences between the carrying amounts and the tax bases of assets and liabilities. Valuation allowances are established when necessary to reduce deferred income tax assets when it is more likely than not that a tax benefit will not be realized. We account for uncertain tax positions in accordance with the provisions of ASC 740. We recognize accruals of interest related to unrecognized tax benefits as a component of the income tax provision.
Valuation of Share-based Compensation Plans	Valuation of Share-Based Compensation Plans We have various types of share-based compensation plans and programs, which are administered by our Board of Directors or its Compensation and Personnel Committee. See Note 14 - Share-Based Compensation Plans of the notes to consolidated financial statements for additional information regarding the share-based compensation plans and programs. We account for share-based payments in accordance with the provisions of Accounting Standards Codification Topic 718, “Compensation-Stock Compensation” (“ASC 718”). ASC 718 requires that all share-based payments issued to acquire goods or services, including grants of employee stock options, be recognized in the statement of operations based on their fair values. Compensation expense related to share-based awards is recognized over the requisite service period, which is generally the vesting period. For shares subject to graded vesting, our policy is to apply the straight-line method in recognizing compensation expense. ASC 718 requires the benefits of tax deductions in excess of recognized compensation expense to be recognized in the Consolidated Statements of Operations when the underlying awards vest or are settled.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenues	The following tables provide further disaggregation of our revenues by categories we use to evaluate our financial performance within each of our reportable segments (in thousands): 2019 % of Total 2018 % of United States electrical construction and facilities services: Commercial market sector $ 1,081,737 49 % $ 839,045 43 % Institutional market sector 125,537 6 % 110,046 6 % Hospitality market sector 16,985 1 % 32,338 2 % Manufacturing market sector 462,953 21 % 388,157 20 % Healthcare market sector 88,752 4 % 126,218 6 % Transportation market sector 210,515 9 % 284,464 14 % Water and wastewater market sector 19,921 1 % 23,337 1 % Short duration projects (1) 158,619 7 % 120,109 6 % Service work 54,955 2 % 34,105 2 % 2,219,974 1,957,819 Less intersegment revenues (3,374 ) (3,496 ) Total segment revenues $ 2,216,600 $ 1,954,323 2019 % of 2018 % of United States mechanical construction and facilities services: Commercial market sector $ 1,185,129 36 % $ 1,057,542 35 % Institutional market sector 313,409 9 % 289,882 10 % Hospitality market sector 35,385 1 % 93,827 3 % Manufacturing market sector 533,699 16 % 393,637 13 % Healthcare market sector 304,622 9 % 240,818 8 % Transportation market sector 32,686 1 % 19,415 1 % Water and wastewater market sector 202,428 6 % 176,546 6 % Short duration projects (1) 365,721 11 % 318,413 11 % Service work 378,839 11 % 385,671 13 % 3,351,918 2,975,751 Less intersegment revenues (11,581 ) (12,908 ) Total segment revenues $ 3,340,337 $ 2,962,843 ________ (1) Represents those projects which generally are completed within three months or less. 2019 % of 2018 % of United States building services: Commercial site-based services $ 571,345 27 % $ 519,641 28 % Government site-based services 176,282 8 % 213,677 11 % Mechanical services 1,238,420 59 % 1,032,082 55 % Energy services 120,825 6 % 110,085 6 % Total segment revenues $ 2,106,872 $ 1,875,485 2019 % of 2018 % of United States industrial services: Field services $ 922,308 85 % $ 752,458 82 % Shop services 165,235 15 % 170,651 18 % Total segment revenues 1,087,543 923,109 Total United States operations $ 8,751,352 $ 7,715,760 2019 % of 2018 % of United Kingdom building services: Service work $ 212,876 50 % $ 216,880 52 % Projects & extras 210,383 50 % 197,991 48 % Total segment revenues $ 423,259 $ 414,871 Total worldwide operations $ 9,174,611 $ 8,130,631
Contract Assets and Contract Liabilities	Net contract liabilities consisted of the following (in thousands): 2019 2018 Contract assets, current $ 177,830 $ 158,243 Contract assets, non-current — — Contract liabilities, current (623,642 ) (552,290 ) Contract liabilities, non-current (2,142 ) (2,069 ) Net contract liabilities $ (447,954 ) $ (396,116 )
Net Contract Liabilities on Uncompleted Construction Projects	Included within net contract liabilities were $406.6 million and $359.2 million of net contract liabilities on uncompleted construction projects as of December 31, 2019 and 2018, respectively, as follows (in thousands): 2019 2018 Costs incurred on uncompleted construction contracts $ 9,885,192 $ 8,656,642 Estimated earnings, thereon 1,349,338 1,172,224 11,234,530 9,828,866 Less: billings to date 11,641,082 10,188,023 $ (406,552 ) $ (359,157 )
Remaining Performance Obligations	The following table presents the transaction price allocated to remaining unsatisfied performance obligations (“remaining performance obligations”) for each of our reportable segments and their respective percentages of total remaining performance obligations (in thousands, except for percentages): 2019 % of Total Remaining performance obligations: United States electrical construction and facilities services $ 1,036,216 26 % United States mechanical construction and facilities services 2,229,090 55 % United States building services 542,269 13 % United States industrial services 104,613 3 % Total United States operations 3,912,188 97 % United Kingdom building services 124,176 3 % Total worldwide operations $ 4,036,364 100 %
Remaining Performance Obligations, Expected Timing of Satisfaction	Refer to the table below for additional information regarding our remaining performance obligations, including an estimate of when we expect to recognize such remaining performance obligations as revenue (in thousands): Within one year Greater than one year Remaining performance obligations: United States electrical construction and facilities services $ 861,268 $ 174,948 United States mechanical construction and facilities services 1,802,865 426,225 United States building services 532,540 9,729 United States industrial services 104,613 — Total United States operations 3,301,286 610,902 United Kingdom building services 83,558 40,618 Total worldwide operations $ 3,384,844 $ 651,520

Disposition Of Assets (Tables)

Disposition Of Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Discontinued Operations and Disposal Groups [Abstract]
Components Of The Results Of Discontinued Operations From Construction Operations In The United Kingdom Segment	The results of discontinued operations for the years ended December 31, 2018 and 2017 were as follows (in thousands): 2018 2017 Revenues $ — $ 863 Loss from discontinued operation, net of income taxes $ (2,345 ) $ (857 ) Diluted loss per share from discontinued operation $ (0.04 ) $ (0.01 )

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Calculation Of Basic And Diluted Earnings (Loss) Per Common Share	The following tables summarize our calculation of Basic and Diluted Earnings (Loss) per Common Share (“EPS”) for the years ended December 31, 2019 , 2018 , and 2017 (in thousands, except share and per share data): 2019 2018 2017 Numerator: Income from continuing operations attributable to EMCOR Group, Inc. common stockholders $ 325,140 $ 285,876 $ 228,053 Loss from discontinued operation, net of income taxes — (2,345 ) (857 ) Net income attributable to EMCOR Group, Inc. common stockholders $ 325,140 $ 283,531 $ 227,196 Denominator: Weighted average shares outstanding used to compute basic earnings (loss) per common share 56,208,280 58,112,838 59,254,256 Effect of dilutive securities—Share-based awards 311,001 330,629 364,713 Shares used to compute diluted earnings (loss) per common share 56,519,281 58,443,467 59,618,969 Basic earnings (loss) per common share: From continuing operations attributable to EMCOR Group, Inc. common stockholders $ 5.78 $ 4.92 $ 3.85 From discontinued operation — (0.04 ) (0.01 ) Net income attributable to EMCOR Group, Inc. common stockholders $ 5.78 $ 4.88 $ 3.84 Diluted earnings (loss) per common share: From continuing operations attributable to EMCOR Group, Inc. common stockholders $ 5.75 $ 4.89 $ 3.83 From discontinued operation — (0.04 ) (0.01 ) Net income attributable to EMCOR Group, Inc. common stockholders $ 5.75 $ 4.85 $ 3.82

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2019
Inventory Disclosure [Abstract]
Inventories	Inventories as of December 31, 2019 and 2018 consist of the following amounts (in thousands): 2019 2018 Raw materials and construction materials $ 31,365 $ 30,006 Work in process 9,081 12,315 Inventories $ 40,446 $ 42,321

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, plant and equipment in the accompanying Consolidated Balance Sheets consisted of the following amounts as of December 31, 2019 and 2018 (in thousands): 2019 2018 Machinery and equipment $ 166,087 $ 151,339 Vehicles 59,116 58,205 Furniture and fixtures 22,123 20,655 Computer hardware/software 104,916 98,415 Land, buildings and leasehold improvements 113,020 97,937 Construction in progress 10,236 14,443 Finance lease right-of-use assets (1) 9,609 — 485,107 440,994 Accumulated depreciation and amortization (328,920 ) (306,643 ) $ 156,187 $ 134,351 _________________ (1) Finance lease right-of-use assets are recorded net of accumulated amortization. Prior to the adoption of ASC 842 on January 1, 2019, assets under capital leases were recorded as machinery and equipment or computer hardware/software.

Goodwill and Identifiable Int_2

Goodwill and Identifiable Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The changes in the carrying amount of goodwill by reportable segment during the years ended December 31, 2019 and 2018 were as follows (in thousands): United States electrical construction and facilities services segment United States mechanical construction and facilities services segment United States building services segment United States Total Balance at December 31, 2017 $ 125,707 $ 256,265 $ 255,733 $ 327,188 $ 964,893 Acquisitions, sales and purchase price adjustments 7,500 56 18,438 — 25,994 Balance at December 31, 2018 133,207 256,321 274,171 327,188 990,887 Acquisitions, sales and purchase price adjustments 9,338 48,699 14,987 — 73,024 Intersegment transfers — (5,800 ) — 5,800 — Balance at December 31, 2019 $ 142,545 $ 299,220 $ 289,158 $ 332,988 $ 1,063,911
Schedule of Intangible Assets	Identifiable intangible assets as of December 31, 2019 and 2018 consist of the following (in thousands): December 31, 2019 Gross Carrying Amount Accumulated Amortization Accumulated Impairment Charge Total Contract backlog $ 66,745 $ (61,651 ) $ — $ 5,094 Developed technology/Vendor network 95,661 (60,156 ) — 35,505 Customer relationships 644,755 (277,601 ) (4,834 ) 362,320 Trade names (amortized) 31,148 (21,830 ) — 9,318 Trade names (unamortized) 251,440 — (52,233 ) 199,207 Total $ 1,089,749 $ (421,238 ) $ (57,067 ) $ 611,444 December 31, 2018 Gross Carrying Amount Accumulated Amortization Accumulated Impairment Charge Total Contract backlog $ 58,945 $ (56,812 ) $ — $ 2,133 Developed technology/Vendor network 95,661 (55,318 ) — 40,343 Customer relationships 522,855 (240,073 ) (4,834 ) 277,948 Trade names (amortized) 31,148 (20,893 ) — 10,255 Trade names (unamortized) 209,840 — (52,233 ) 157,607 Total $ 918,449 $ (373,096 ) $ (57,067 ) $ 488,286
Schedule of Estimated Future Amortization Expense	The following table presents the estimated future amortization expense of identifiable intangible assets in the following years (in thousands): 2020 $ 56,680 2021 50,792 2022 48,589 2023 47,650 2024 47,300 Thereafter 161,226 $ 412,237

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule Of Debt	Long-term debt in the accompanying Consolidated Balance Sheets consisted of the following amounts as of December 31, 2019 and 2018 (in thousands): 2019 2018 Revolving credit facility $ 50,000 $ 25,000 Term loan, interest payable at varying amounts through 2021 254,431 269,620 Unamortized debt issuance costs (1,879 ) (3,065 ) Finance lease liabilities 9,679 4,213 Other — 9 Total debt 312,231 295,777 Less: current maturities 18,092 16,013 Total long-term debt $ 294,139 $ 279,764

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Schedule Of Assets And Liabilities Carried At Fair Value Measured On A Recurring Basis	The following tables provide the assets and liabilities carried at fair value measured on a recurring basis as of December 31, 2019 and 2018 (in thousands): Assets at Fair Value as of December 31, 2019 Asset Category Level 1 Level 2 Level 3 Total Cash and cash equivalents (1) $ 358,818 $ — $ — $ 358,818 Restricted cash (2) 1,102 — — 1,102 Deferred compensation plan assets (3) 30,295 — — 30,295 Total $ 390,215 $ — $ — $ 390,215 Assets at Fair Value as of December 31, 2018 Asset Category Level 1 Level 2 Level 3 Total Cash and cash equivalents (1) $ 363,907 $ — $ — $ 363,907 Restricted cash (2) 2,307 — — 2,307 Deferred compensation plan assets (3) 23,124 — — 23,124 Total $ 389,338 $ — $ — $ 389,338 _________________ (1) Cash and cash equivalents consist of deposit accounts and money market funds with original maturity dates of three months or less, which are Level 1 assets. At December 31, 2019 and 2018 , we had $164.0 million and $161.3 million , respectively, in money market funds. (2) Restricted cash is classified as “Prepaid expenses and other” in the Consolidated Balance Sheets. Restricted cash primarily represents cash held in account for use on customer contracts. (3) Deferred compensation plan assets are classified as “Other assets” in the Consolidated Balance Sheets.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax From Continuing Operations	For the years ended December 31, 2019 , 2018 , and 2017 , our income tax provision was calculated based on income from continuing operations before income taxes as follows (in thousands): 2019 2018 2017 United States $ 430,253 $ 375,408 $ 303,854 Foreign 20,636 19,620 14,895 $ 450,889 $ 395,028 $ 318,749
Schedule of Income Tax Provision	The income tax provision in the accompanying Consolidated Statements of Operations for the years ended December 31, 2019 , 2018 , and 2017 consisted of the following (in thousands): 2019 2018 2017 Current provision: Federal $ 89,264 $ 75,405 $ 120,317 State and local 31,099 28,063 23,496 Foreign 3,685 1,389 244 124,048 104,857 144,057 Deferred provision (benefit) 1,701 4,249 (53,358 ) $ 125,749 $ 109,106 $ 90,699
Schedule of U.S. Statutory Income Tax Rates From Continuing Operations	Items accounting for the differences between income taxes computed at the federal statutory rate and the income tax provision for the years ended December 31, 2019 , 2018 , and 2017 were as follows (in thousands): 2019 2018 2017 Federal income taxes at the statutory rate $ 94,687 $ 82,946 $ 111,562 State and local income taxes, net of federal tax benefits 24,904 21,827 15,736 State tax reserves — (7 ) (2,543 ) Permanent differences 7,149 6,584 4,916 Domestic manufacturing deduction — — (10,387 ) Excess tax benefit from share-based compensation (733 ) (1,227 ) (1,341 ) Goodwill impairment — — 17,055 Foreign income taxes (including UK statutory rate changes) (170 ) 70 (2,586 ) Impact of federal rate change on net deferred tax liabilities — — (39,343 ) Federal tax reserves — (67 ) (1,247 ) Other (88 ) (1,020 ) (1,123 ) $ 125,749 $ 109,106 $ 90,699
Schedule of Deferred Tax Assets and Liabilities	The deferred income tax assets and deferred income tax liabilities recorded for the years ended December 31, 2019 and 2018 were as follows (in thousands): 2019 2018 Deferred income tax assets: Excess of amounts expensed for financial statement purposes over amounts deducted for income tax purposes: Insurance liabilities $ 47,022 $ 44,192 Pension liability 2,733 3,204 Operating lease liabilities (1) 68,158 — Deferred compensation 32,685 29,300 Other (including liabilities and reserves) 25,647 27,400 Total deferred income tax assets 176,245 104,096 Valuation allowance for deferred tax assets (3,463 ) (3,855 ) Net deferred income tax assets 172,782 100,241 Deferred income tax liabilities: Costs capitalized for financial statement purposes and deducted for income tax purposes: Goodwill and identifiable intangible assets (156,604 ) (152,761 ) Operating lease right-of-use assets (1) (65,090 ) — Depreciation of property, plant and equipment (18,622 ) (14,904 ) Other (4,212 ) (3,424 ) Total deferred income tax liabilities (244,528 ) (171,089 ) Net deferred income tax liabilities $ (71,746 ) $ (70,848 )

Share-Based Compensation Plans

Share-Based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Schedule of activity of stock options and awards of shares and stock units	The following table summarizes activity regarding our stock options and awards of shares and stock units since December 31, 2016: Stock Options Restricted Stock Units Shares Weighted Average Price Shares Weighted Average Price Balance, December 31, 2016 143,000 $ 23.06 Balance, December 31, 2016 492,288 $ 44.93 Granted — — Granted 198,179 $ 68.33 Expired — — Forfeited (1,200 ) $ 60.68 Exercised (50,000 ) $ 20.42 Vested (180,395 ) $ 44.57 Balance, December 31, 2017 93,000 $ 24.48 Balance, December 31, 2017 508,872 $ 54.13 Granted — — Granted 135,259 $ 80.37 Expired — — Forfeited (1,250 ) $ 71.27 Exercised (53,000 ) $ 24.48 Vested (166,295 ) $ 48.44 Balance, December 31, 2018 40,000 $ 24.48 Balance, December 31, 2018 476,586 $ 63.52 Granted — — Granted 169,766 $ 64.34 Expired — — Forfeited (2,545 ) $ 71.88 Exercised (20,000 ) $ 24.48 Vested (226,229 ) $ 51.64 Balance, December 31, 2019 20,000 $ 24.48 Balance, December 31, 2019 417,578 $ 70.24
Summary of information about stock options	The following table summarizes information about our outstanding stock options as of December 31, 2019 : Stock Options Outstanding and Exercisable Range of Exercise Prices Number Weighted Average Remaining Life Weighted Average Exercise Price $24.48 20,000 0.45 Years $24.48

Retirement Plans (Tables)

Retirement Plans (Tables)	12 Months Ended
	Dec. 31, 2019
Retirement Benefits [Abstract]
Schedule of Changes in Benefit Obligations and Assets	The change in benefit obligations and assets of the UK Plan for the years ended December 31, 2019 and 2018 consisted of the following components (in thousands): 2019 2018 Change in pension benefit obligation Benefit obligation at beginning of year $ 281,776 $ 332,618 Interest cost 7,961 8,085 Actuarial loss (gain) 32,866 (27,755 ) Benefits paid (12,059 ) (14,318 ) Foreign currency exchange rate changes 12,222 (16,854 ) Benefit obligation at end of year 322,766 281,776 Change in pension plan assets Fair value of plan assets at beginning of year 264,194 295,968 Actual return on plan assets 38,808 (6,489 ) Employer contributions 4,428 4,742 Benefits paid (12,059 ) (14,318 ) Foreign currency exchange rate changes 11,630 (15,709 ) Fair value of plan assets at end of year 307,001 264,194 Funded status at end of year $ (15,765 ) $ (17,582 )
Schedule of Net Periodic Benefit Cost Not yet Recognized	Amounts not yet reflected in net periodic pension cost and included in accumulated other comprehensive loss were as follows (in thousands): 2019 2018 Unrecognized losses $ 94,211 $ 86,768
Schedule of Weighted Average Assumptions Used To Calculate Benefit Obligation	The weighted average assumptions used to determine benefit obligations as of December 31, 2019 and 2018 were as follows: 2019 2018 Discount rate 2.1 % 2.9 %
Schedule of Weighted Average Assumptions Used To Calculate Net Periodic Pension Cost	The weighted average assumptions used to determine net periodic pension cost for the years ended December 31, 2019 , 2018 , and 2017 were as follows: 2019 2018 2017 Discount rate 2.9 % 2.5 % 2.7 % Annual rate of return on plan assets 4.9 % 5.0 % 5.3 %
Components Of Net Periodic Pension Cost	The components of net periodic pension cost (income) of the UK Plan for the years ended December 31, 2019 , 2018 , and 2017 were as follows (in thousands): 2019 2018 2017 Interest cost $ 7,961 $ 8,085 $ 8,622 Expected return on plan assets (12,165 ) (13,797 ) (13,508 ) Amortization of unrecognized loss 2,342 2,630 2,942 Net periodic pension cost (income) $ (1,862 ) $ (3,082 ) $ (1,944 )
Schedule of Weighted Average Asset Allocations and Weighted Average Target Allocations	The weighted average asset allocations and weighted average target allocations at December 31, 2019 and 2018 were as follows: Asset Category Target December 31, December 31, Debt 65.0 % 70.6 % 71.2 % Equity 15.0 % 10.5 % 13.4 % Cash 10.0 % 10.5 % 6.1 % Real estate 10.0 % 8.4 % 9.3 % Total 100.0 % 100.0 % 100.0 %
Schedule of Plan Assets Fair Value Hierarchy	The following tables set forth the fair value of assets of the UK Plan as of December 31, 2019 and 2018 (in thousands): Assets at Fair Value as of December 31, 2019 Asset Category Level 1 Level 2 Level 3 Total Corporate debt funds $ — $ 64,314 $ — $ 64,314 Government bond funds — 49,164 — 49,164 Equity funds — 32,356 — 32,356 Cash 32,240 — — 32,240 Total plan assets in fair value hierarchy $ 32,240 $ 145,834 $ — 178,074 Plan assets measured using NAV as a practical expedient: (1) Debt funds 103,188 Real estate funds 25,739 Total plan assets at fair value $ 307,001 Assets at Fair Value as of December 31, 2018 Asset Category Level 1 Level 2 Level 3 Total Corporate debt funds $ — $ 37,703 $ — $ 37,703 Government bond funds — 52,445 — 52,445 Equity funds — 35,425 — 35,425 Cash 16,097 — — 16,097 Total plan assets in fair value hierarchy $ 16,097 $ 125,573 $ — 141,670 Plan assets measured using NAV as a practical expedient: (1) Debt funds 98,077 Real estate funds 24,447 Total plan assets at fair value $ 264,194
Schedule of Expected Benefit Payments	The following estimated benefit payments are expected to be paid in the following years (in thousands): Pension Benefit Payments 2020 $ 12,887 2021 $ 13,240 2022 $ 13,603 2023 $ 13,976 2024 $ 14,358 Succeeding five years $ 77,912
Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets	The following table shows certain information for the UK Plan where the accumulated benefit obligation is in excess of plan assets as of December 31, 2019 and 2018 (in thousands): 2019 2018 Projected benefit obligation $ 322,766 $ 281,776 Accumulated benefit obligation $ 322,766 $ 281,776 Fair value of plan assets $ 307,001 $ 264,194
Schedule of Multiemployer Plans	The following table lists all domestic MEPPs to which our contributions exceeded $2.0 million in 2019 . Additionally, this table also lists all domestic MEPPs to which we contributed in 2019 in excess of $0.5 million for MEPPs in the critical status, “red zone,” and $1.0 million for MEPPs in the endangered status, “orange or yellow zones,” as defined by the PPA (in thousands): Pension Fund EIN/Pension Plan Number PPA Zone Status (1) FIP/RP Status Contributions Contributions greater than 5% of total plan contributions (2) Expiration date or range of expiration dates of CBA(s) 2019 2018 2019 2018 2017 National Electrical Benefit Fund 53-0181657 001 Green Green NA $ 16,901 $ 10,700 $ 11,572 No January 2020 to National Automatic Sprinkler Industry Pension Fund 52-6054620 001 Red Red Implemented 15,924 14,888 14,228 No June 2020 to June 2022 Plumbers & Pipefitters National Pension Fund 52-6152779 001 Yellow Yellow Implemented 13,821 11,868 12,550 No February 2020 to August 2026 Sheet Metal Workers National Pension Fund 52-6112463 001 Yellow Yellow Implemented 11,713 10,895 12,895 No April 2020 to Pension, Hospitalization & Benefit Plan of the Electrical Industry-Pension Trust Account 13-6123601 001 Green Green NA 10,075 10,469 9,489 No April 2020 to April 2022 Electrical Workers Local No. 26 Pension Trust Fund 52-6117919 001 Green Green NA 8,434 5,485 4,441 Yes January 2020 to July 2021 Plumbers Pipefitters & Mechanical Equipment Service Local Union 392 Pension Plan 31-0655223 001 Red Red Implemented 6,412 6,047 6,084 Yes June 2022 Southern California IBEW-NECA Pension Trust Fund 95-6392774 001 Yellow Yellow Implemented 6,277 5,754 3,669 No May 2020 to Central Pension Fund of the IUOE & Participating Employers 36-6052390 001 Green Green NA 6,253 6,384 6,070 No February 2020 to Sheet Metal Workers Pension Plan of Northern California 51-6115939 001 Red Red Implemented 6,233 5,488 6,023 No June 2020 to June 2026 Arizona Pipe Trades Pension Trust Fund 86-6025734 001 Green Green NA 6,071 2,640 1,662 Yes June 2020 Edison Pension Plan 93-6061681 001 Green Green NA 5,361 3,140 1,628 Yes December 2020 Pipefitters Union Local 537 Pension Fund 51-6030859 001 Green Green NA 4,754 6,038 4,057 Yes September 2020 to August 2021 Pension Fund EIN/Pension Plan Number PPA Zone Status (1) FIP/RP Status Contributions Contributions greater than 5% of total plan contributions (2) Expiration date or range of expiration dates of CBA(s) 2019 2018 2019 2018 2017 Heating, Piping & Refrigeration Pension Fund 52-1058013 001 Green Green NA 4,185 2,619 2,437 No June 2020 to July 2021 U.A. Local 393 Pension Trust Fund Defined Benefit 94-6359772 002 Green Green NA 3,858 4,298 1,540 Yes June 2020 to June 2021 San Diego Electrical Pension Plan 95-6101801 001 Green Green NA 3,843 3,008 2,862 Yes May 2020 to May 2022 Eighth District Electrical Pension Fund 84-6100393 001 Green Green NA 3,590 3,486 3,786 Yes May 2020 to May 2022 Southern California Pipe Trades Retirement Fund 51-6108443 001 Green Green NA 3,274 3,095 3,907 No June 2020 to Electrical Contractors Association and Local Union 134, IBEW Joint Pension Trust of Chicago Pension Plan 2 51-6030753 002 Green Green NA 3,204 4,308 5,537 No May 2020 Northern California Pipe Trades Pension Plan 94-3190386 001 Green Green NA 3,077 3,104 2,963 No June 2020 to June 2021 NECA-IBEW Pension Trust Fund 51-6029903 001 Green Green NA 2,528 2,650 3,060 No May 2020 to December 2020 U.A. Plumbers Local 24 Pension Fund 22-6042823 001 Green Green NA 2,460 3,461 3,092 Yes April 2020 Sheet Metal Workers Pension Plan of Southern California, Arizona & Nevada 95-6052257 001 Yellow Yellow Implemented 2,423 1,934 3,268 No June 2020 to June 2024 Connecticut Plumbers & Pipefitters Pension Fund 06-6050353 001 Green Green NA 2,231 2,104 1,988 Yes June 2021 U.A. Local 38 Defined Benefit Pension Plan 94-1285319 001 Green Green NA 2,030 1,551 2,097 No June 2020 to June 2023 Plumbing & Pipe Fitting Local 219 Pension Fund 34-6682376 001 Red Red Implemented 1,937 2,197 1,335 Yes May 2020 Boilermaker-Blacksmith National Pension Trust 48-6168020 001 Red Red Implemented 1,681 1,446 1,083 No September 2020 to Plumbers & Pipefitters Local Union No. 502 & 633 Pension Fund 61-6078145 001 Yellow Yellow Implemented 1,596 1,167 801 No May 2020 to July 2022 Plumbers & Pipefitters Local 162 Pension Fund 31-6125999 001 Yellow Yellow Implemented 1,124 1,273 801 Yes May 2020 to May 2022 Steamfitters Local Union No. 420 Pension Plan 23-2004424 001 Red Red Implemented 641 706 687 No May 2020 Other Multiemployer Pension Plans 53,567 48,026 43,604 Various Total Contributions $ 215,478 $ 190,229 $ 179,216 _________________ (1) The zone status represents the most recent available information for the respective MEPP, which may be 2018 or earlier for the 2019 year and 2017 or earlier for the 2018 year. (2) This information was obtained from the respective plan’s Form 5500 (“Forms”) for the most current available filing. These dates may not correspond with our fiscal year contributions. The above noted percentages of contributions are based upon disclosures contained in the plans’ Forms. Those Forms, among other things, disclose the names of individual participating employers whose annual contributions account for more than 5% of the aggregate annual amount contributed by all participating employers for a plan year. Accordingly, if the annual contribution of two or more of our subsidiaries each accounted for less than 5% of such contributions, but in the aggregate accounted for in excess of 5% of such contributions, that greater percentage is not available and accordingly is not disclosed.

Restructuring and Related Activ

Restructuring and Related Activities (Tables)	12 Months Ended
	Dec. 31, 2019
Restructuring and Related Activities [Abstract]
Schedule of Restructuring Reserve	The changes in restructuring activity by reportable segment during the years ended December 31, 2019 and 2018 were as follows (in thousands): United States United States building services segment Corporate administration Total Balance at December 31, 2017 $ 452 $ 40 $ — $ 492 Charges — 882 1,424 2,306 Payments (422 ) (746 ) — (1,168 ) Balance at December 31, 2018 30 176 1,424 1,630 Charges 445 1,078 — 1,523 Payments (30 ) (842 ) (723 ) (1,595 ) Balance at December 31, 2019 $ 445 $ 412 $ 701 $ 1,558

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Schedule of Lease Assets and Liabilities	The following table presents the lease-related assets and liabilities reported in the Consolidated Balance Sheet as of December 31, 2019 (in thousands): Classification on the Consolidated Balance Sheet December 31, Assets Operating lease assets Operating lease right-of-use assets $ 245,471 Finance lease assets Property, plant and equipment, net 9,609 Total lease assets $ 255,080 Liabilities Current Operating Operating lease liabilities, current $ 53,144 Finance Current maturities of long-term debt and finance lease liabilities 4,088 Noncurrent Operating Operating lease liabilities, long-term 204,950 Finance Long-term debt and finance lease liabilities 5,591 Total lease liabilities $ 267,773
Schedule of Lease Cost	The following table presents information related to lease expense for the year ended December 31, 2019 (in thousands): 2019 Finance lease expense: Amortization expense $ 4,575 Interest expense 427 Operating lease expense 66,650 Short-term lease expense 149,528 Variable lease expense 4,924 Total lease expense $ 226,104 Rent expense for operating leases and other rental items, including short-term equipment rentals, for the years ended December 31, 2018 and 2017 was approximately $191.8 million and $166.5 million , respectively. For the years ended December 31, 2019 , 2018 , and 2017 , sublease rental income was approximately $0.5 million , $0.6 million , and $0.6 million , respectively. Lease Term and Discount Rate The following table presents certain information related to lease terms and discount rates for leases as of December 31, 2019 : December 31, Weighted-average remaining lease term: Operating leases 6.7 years Finance leases 2.9 years Weighed-average discount rate: Operating leases 4.04 % Finance leases 4.16 % Other Information The following table presents supplemental cash flow information related to leases for the year ended December 31, 2019 (in thousands): 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows used for operating leases $ 65,757 Operating cash flows used for finance leases $ 427 Financing cash flows used for finance leases $ 4,571 Right-of-use assets obtained in exchange for new operating lease liabilities $ 84,089 Right-of-use assets obtained in exchange for new finance lease liabilities $ 5,311
Schedule of Maturity of Operating Leases	The following table reconciles future minimum lease payments on an undiscounted cash flow basis to the lease liabilities reported in the Consolidated Balance Sheet as of December 31, 2019 (in thousands): Operating Leases Finance Leases 2020 $ 62,457 $ 4,391 2021 50,505 3,039 2022 42,155 1,807 2023 35,223 743 2024 26,049 138 Thereafter 80,661 129 Total minimum lease payments 297,050 10,247 Less: Amount of lease payments representing interest (38,956 ) (568 ) Present value of future minimum lease payments $ 258,094 $ 9,679 Current portion of lease liabilities $ 53,144 $ 4,088 Noncurrent portion of lease liabilities 204,950 5,591 Present value of future minimum lease payments $ 258,094 $ 9,679
Schedule of Maturity of Finance Leases	The following table reconciles future minimum lease payments on an undiscounted cash flow basis to the lease liabilities reported in the Consolidated Balance Sheet as of December 31, 2019 (in thousands): Operating Leases Finance Leases 2020 $ 62,457 $ 4,391 2021 50,505 3,039 2022 42,155 1,807 2023 35,223 743 2024 26,049 138 Thereafter 80,661 129 Total minimum lease payments 297,050 10,247 Less: Amount of lease payments representing interest (38,956 ) (568 ) Present value of future minimum lease payments $ 258,094 $ 9,679 Current portion of lease liabilities $ 53,144 $ 4,088 Noncurrent portion of lease liabilities 204,950 5,591 Present value of future minimum lease payments $ 258,094 $ 9,679

Additional Cash Flow Informat_2

Additional Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2019
Supplemental Cash Flow Information [Abstract]
Schedule of Cash Flow, Supplemental Disclosures	The following presents information about cash paid for interest and income taxes for the years ended December 31, 2019 , 2018 , and 2017 (in thousands): 2019 2018 2017 Cash paid during the year for: Interest $ 12,683 $ 12,435 $ 11,456 Income taxes $ 126,169 $ 123,651 $ 130,226

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Information About Industry Segments And Geographic Areas	The following tables present information about industry segments and geographic areas for the years ended December 31, 2019 , 2018 , and 2017 (in thousands): 2019 2018 2017 Revenues from unrelated entities: United States electrical construction and facilities services $ 2,216,600 $ 1,954,323 $ 1,829,567 United States mechanical construction and facilities services 3,340,337 2,962,843 2,880,148 United States building services 2,106,872 1,875,485 1,753,703 United States industrial services 1,087,543 923,109 882,836 Total United States operations 8,751,352 7,715,760 7,346,254 United Kingdom building services 423,259 414,871 340,745 Total worldwide operations $ 9,174,611 $ 8,130,631 $ 7,686,999 Total revenues: United States electrical construction and facilities services $ 2,220,582 $ 1,959,978 $ 1,836,985 United States mechanical construction and facilities services 3,370,960 2,998,918 2,911,033 United States building services 2,182,390 1,942,663 1,812,763 United States industrial services 1,111,264 930,724 885,198 Less intersegment revenues (133,844 ) (116,523 ) (99,725 ) Total United States operations 8,751,352 7,715,760 7,346,254 United Kingdom building services 423,259 414,871 340,745 Total worldwide operations $ 9,174,611 $ 8,130,631 $ 7,686,999 2019 2018 2017 Operating income (loss): United States electrical construction and facilities services $ 161,684 $ 139,430 $ 150,001 United States mechanical construction and facilities services 225,040 219,853 192,167 United States building services 114,754 93,827 81,720 United States industrial services 44,340 27,671 39,313 Total United States operations 545,818 480,781 463,201 United Kingdom building services 18,323 15,930 12,905 Corporate administration (101,726 ) (90,415 ) (87,808 ) Restructuring expenses (1,523 ) (2,306 ) (1,577 ) Impairment loss on goodwill and identifiable intangible assets — (907 ) (57,819 ) Total worldwide operations 460,892 403,083 328,902 Other corporate items: Net periodic pension (cost) income 1,553 2,743 1,652 Interest expense (13,821 ) (13,544 ) (12,770 ) Interest income 2,265 2,746 965 Income from continuing operations before income taxes $ 450,889 $ 395,028 $ 318,749 Capital expenditures: United States electrical construction and facilities services $ 5,876 $ 5,993 $ 4,797 United States mechanical construction and facilities services 7,890 7,504 6,665 United States building services 14,291 10,414 10,745 United States industrial services 15,802 18,386 9,696 Total United States operations 43,859 42,297 31,903 United Kingdom building services 3,598 870 2,166 Corporate administration 975 312 615 Total worldwide operations $ 48,432 $ 43,479 $ 34,684 Depreciation and amortization of property, plant and equipment: United States electrical construction and facilities services $ 7,550 $ 6,221 $ 6,545 United States mechanical construction and facilities services 8,764 7,803 7,504 United States building services 12,728 10,324 11,051 United States industrial services 11,154 9,943 10,589 Total United States operations 40,196 34,291 35,689 United Kingdom building services 2,942 3,447 3,371 Corporate administration 807 734 855 Total worldwide operations $ 43,945 $ 38,472 $ 39,915 2019 2018 2017 Contract assets: United States electrical construction and facilities services $ 50,813 $ 38,412 $ 35,060 United States mechanical construction and facilities services 61,225 49,302 50,302 United States building services 30,428 33,304 26,028 United States industrial services 9,820 14,117 3,715 Total United States operations 152,286 135,135 115,105 United Kingdom building services 25,544 23,108 7,516 Total worldwide operations $ 177,830 $ 158,243 $ 122,621 Contract liabilities: United States electrical construction and facilities services $ 173,967 $ 163,951 $ 178,454 United States mechanical construction and facilities services 317,083 280,846 288,699 United States building services 97,588 79,281 48,481 United States industrial services 12,404 12,307 4,615 Total United States operations 601,042 536,385 520,249 United Kingdom building services 22,600 15,905 3,907 Total worldwide operations $ 623,642 $ 552,290 $ 524,156 Long-lived assets: United States electrical construction and facilities services $ 215,780 $ 201,333 $ 180,990 United States mechanical construction and facilities services 530,561 334,628 340,030 United States building services 458,915 436,887 409,718 United States industrial services 615,233 630,340 643,124 Total United States operations 1,820,489 1,603,188 1,573,862 United Kingdom building services 9,622 9,264 11,729 Corporate administration 1,431 1,072 1,494 Total worldwide operations $ 1,831,542 $ 1,613,524 $ 1,587,085 Total assets: United States electrical construction and facilities services $ 834,802 $ 702,112 $ 617,471 United States mechanical construction and facilities services 1,536,325 1,081,005 1,071,164 United States building services 996,664 846,221 764,085 United States industrial services 829,793 864,446 798,975 Total United States operations 4,197,584 3,493,784 3,251,695 United Kingdom building services 181,147 146,379 131,806 Corporate administration 451,627 448,644 582,403 Total worldwide operations $ 4,830,358 $ 4,088,807 $ 3,965,904

Selected Unaudited Quarterly _2

Selected Unaudited Quarterly Information (Tables)	12 Months Ended
	Dec. 31, 2019
Selected Quarterly Financial Information [Abstract]
Schedule of Quarterly Financial Information	March 31 June 30 Sept. 30 Dec. 31 2019 Quarterly Results Revenues $ 2,158,728 $ 2,324,202 $ 2,287,741 $ 2,403,940 Gross profit $ 308,754 $ 346,380 $ 335,987 $ 364,747 Net income attributable to EMCOR Group, Inc. $ 72,410 $ 83,972 $ 81,834 $ 86,924 Basic EPS from continuing operations $ 1.29 $ 1.49 $ 1.46 $ 1.54 Basic EPS from discontinued operation — — — — $ 1.29 $ 1.49 $ 1.46 $ 1.54 Diluted EPS from continuing operations $ 1.28 $ 1.49 $ 1.45 $ 1.54 Diluted EPS from discontinued operation — — — — $ 1.28 $ 1.49 $ 1.45 $ 1.54 March 31 June 30 Sept. 30 Dec. 31 2018 Quarterly Results Revenues $ 1,900,388 $ 1,953,886 $ 2,047,049 $ 2,229,308 Gross profit $ 269,119 $ 290,844 $ 309,339 $ 336,151 Impairment loss on identifiable intangible assets $ — $ 907 $ — $ — Net income attributable to EMCOR Group, Inc. $ 55,374 $ 70,816 $ 79,373 $ 77,968 Basic EPS from continuing operations $ 0.95 $ 1.22 $ 1.37 $ 1.39 Basic EPS from discontinued operation (0.00 ) (0.00 ) (0.01 ) (0.02 ) $ 0.95 $ 1.22 $ 1.36 $ 1.37 Diluted EPS from continuing operations $ 0.94 $ 1.21 $ 1.36 $ 1.38 Diluted EPS from discontinued operation (0.00 ) (0.00 ) (0.01 ) (0.02 ) $ 0.94 $ 1.21 $ 1.35 $ 1.36

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019
Property, Plant and Equipment [Line Items]
Accounts receivable, net	$ 2,030,813,000	$ 1,773,620,000
Allowance for doubtful accounts	14,466,000	15,361,000
Provision for doubtful accounts	2,628,000	2,123,000	$ 7,264,000
Non-cash expense for impairment of property, plant and equipment	0	0	$ 0
Operating lease right-of-use assets	245,471,000	0
Operating lease liabilities, total	$ 258,094,000
Machinery and Equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Machinery and Equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Vehicles, Furniture and Fixtures, and Computer Hardware and Software | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Vehicles, Furniture and Fixtures, and Computer Hardware and Software | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	7 years
Buildings
Property, Plant and Equipment [Line Items]
Estimated useful life	25 years
Other Current Liabilities
Property, Plant and Equipment [Line Items]
Insurance liabilities, current	$ 48,300,000	44,600,000
Other Noncurrent Liabilities
Property, Plant and Equipment [Line Items]
Insurance liabilities, noncurrent	186,000,000	179,100,000
Prepaid Expenses and Other
Property, Plant and Equipment [Line Items]
Anticipated insurance recoveries, current	13,800,000	12,600,000
Other Assets
Property, Plant and Equipment [Line Items]
Anticipated insurance recoveries, noncurrent	$ 50,900,000	$ 49,300,000
Accounting Standards Update 2016-02 [Member]
Property, Plant and Equipment [Line Items]
Operating lease right-of-use assets				$ 220,200,000
Operating lease liabilities, total				$ 227,100,000

Revenue from Contracts with C_3

Revenue from Contracts with Customers (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Performance obligation satisfied in previous period	$ 0	$ 7,300,000
Change in estimate of transaction price	0	0
Loss on contracts	0
Unbilled revenues for unapproved change orders	33,100,000	25,200,000
Accounts receivable, unapproved contract claims	0	0
Accounts receivable, contractually billed amounts on contracts related to unapproved contract claims	89,000,000	96,100,000
Net billings in excess of costs	406,552,000	359,157,000
Change in net contract liabilities	51,800,000
Change in net billings in excess of costs	47,400,000
Contract asset impairment	0
Accounts receivable, retainage	$ 298,500,000	254,600,000
Accounts receivable, retainage estimated to be collected in next fiscal year	88.00%
Accounts payable, retainage	$ 64,700,000	43,300,000
Accounts payable, retainage estimated to be paid in next fiscal year	86.00%
Remaining performance obligations	$ 4,036,364,000
2019 Acquisitions
Business Acquisition [Line Items]
Increase (decrease) in contract assets from acquisitions	8,200,000
Increase (decrease) in contract liabilities from acquisitions	$ 29,000,000
United States Electrical Construction And Facilities Services | Transportation Sector [Member]
Business Acquisition [Line Items]
Loss on contracts		$ 10,000,000

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Schedule of Disaggregation of Revenues (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenues		$ 2,403,940	$ 2,287,741	$ 2,324,202	$ 2,158,728	$ 2,229,308	$ 2,047,049	$ 1,953,886	$ 1,900,388	$ 9,174,611	$ 8,130,631	$ 7,686,999
UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										8,751,352	7,715,760	7,346,254
United States Electrical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										2,216,600	1,954,323	1,829,567
United States Mechanical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										3,340,337	2,962,843	2,880,148
United States Building Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										2,106,872	1,875,485	1,753,703
United States Industrial Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										1,087,543	923,109	882,836
United Kingdom Building Services | UNITED KINGDOM
Disaggregation of Revenue [Line Items]
Revenues										423,259	414,871	$ 340,745
Operating Segments [Member] | United States Electrical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										2,219,974	1,957,819
Operating Segments [Member] | United States Mechanical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										3,351,918	2,975,751
Intersegment Eliminations [Member] | United States Electrical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										(3,374)	(3,496)
Intersegment Eliminations [Member] | United States Mechanical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										(11,581)	(12,908)
Commercial Market Sector [Member] | Operating Segments [Member] | United States Electrical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 1,081,737	$ 839,045
Percent of individual segment										49.00%	43.00%
Commercial Market Sector [Member] | Operating Segments [Member] | United States Mechanical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 1,185,129	$ 1,057,542
Percent of individual segment										36.00%	35.00%
Institutional Market Sector [Member] | Operating Segments [Member] | United States Electrical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 125,537	$ 110,046
Percent of individual segment										6.00%	6.00%
Institutional Market Sector [Member] | Operating Segments [Member] | United States Mechanical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 313,409	$ 289,882
Percent of individual segment										9.00%	10.00%
Hospitality Market Sector [Member] | Operating Segments [Member] | United States Electrical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 16,985	$ 32,338
Percent of individual segment										1.00%	2.00%
Hospitality Market Sector [Member] | Operating Segments [Member] | United States Mechanical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 35,385	$ 93,827
Percent of individual segment										1.00%	3.00%
Manufacturing Market Sector [Member] | Operating Segments [Member] | United States Electrical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 462,953	$ 388,157
Percent of individual segment										21.00%	20.00%
Manufacturing Market Sector [Member] | Operating Segments [Member] | United States Mechanical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 533,699	$ 393,637
Percent of individual segment										16.00%	13.00%
Healthcare Market Sector [Member] | Operating Segments [Member] | United States Electrical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 88,752	$ 126,218
Percent of individual segment										4.00%	6.00%
Healthcare Market Sector [Member] | Operating Segments [Member] | United States Mechanical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 304,622	$ 240,818
Percent of individual segment										9.00%	8.00%
Transportation Market Sector [Member] | Operating Segments [Member] | United States Electrical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 210,515	$ 284,464
Percent of individual segment										9.00%	14.00%
Transportation Market Sector [Member] | Operating Segments [Member] | United States Mechanical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 32,686	$ 19,415
Percent of individual segment										1.00%	1.00%
Water and Wastewater Market Sector [Member] | Operating Segments [Member] | United States Electrical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 19,921	$ 23,337
Percent of individual segment										1.00%	1.00%
Water and Wastewater Market Sector [Member] | Operating Segments [Member] | United States Mechanical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 202,428	$ 176,546
Percent of individual segment										6.00%	6.00%
Short Duration Projects [Member] | Operating Segments [Member] | United States Electrical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 158,619	$ 120,109
Percent of individual segment										7.00%	6.00%
Short Duration Projects [Member] | Operating Segments [Member] | United States Mechanical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues	[1]									$ 365,721	$ 318,413
Percent of individual segment										11.00%	11.00%
Service Work [Member] | Operating Segments [Member] | United States Electrical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 54,955	$ 34,105
Percent of individual segment										2.00%	2.00%
Service Work [Member] | Operating Segments [Member] | United States Mechanical Construction And Facilities Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 378,839	$ 385,671
Percent of individual segment										11.00%	13.00%
Service Work [Member] | Operating Segments [Member] | United Kingdom Building Services | UNITED KINGDOM
Disaggregation of Revenue [Line Items]
Revenues										$ 212,876	$ 216,880
Percent of individual segment										50.00%	52.00%
Commercial Site-Based Services [Member] | Operating Segments [Member] | United States Building Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 571,345	$ 519,641
Percent of individual segment										27.00%	28.00%
Government Site-Based Services [Member] | Operating Segments [Member] | United States Building Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 176,282	$ 213,677
Percent of individual segment										8.00%	11.00%
Mechanical Services [Member] | Operating Segments [Member] | United States Building Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 1,238,420	$ 1,032,082
Percent of individual segment										59.00%	55.00%
Energy Services [Member] | Operating Segments [Member] | United States Building Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 120,825	$ 110,085
Percent of individual segment										6.00%	6.00%
Field Services [Member] | Operating Segments [Member] | United States Industrial Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 922,308	$ 752,458
Percent of individual segment										85.00%	82.00%
Shop Services [Member] | Operating Segments [Member] | United States Industrial Services | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues										$ 165,235	$ 170,651
Percent of individual segment										15.00%	18.00%
Projects & Extras [Member] | Operating Segments [Member] | United Kingdom Building Services | UNITED KINGDOM
Disaggregation of Revenue [Line Items]
Revenues										$ 210,383	$ 197,991
Percent of individual segment										50.00%	48.00%
[1]	Represents those projects which generally are completed within three months or less.

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Schedule of Contract with Customer, Asset and Liability (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Contract assets	$ 177,830	$ 158,243	$ 122,621
Contract assets, non-current	0	0
Contract liabilities	(623,642)	(552,290)	$ (524,156)
Contract liabilities, non-current	(2,142)	(2,069)
Net contract liabilities	$ (447,954)	$ (396,116)

Revenue from Contracts with C_6

Revenue from Contracts with Customers - Schedule of Net Contract Liabilities on Uncompleted Construction Projects (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Costs incurred on uncompleted construction contracts	$ 9,885,192	$ 8,656,642
Estimated earnings, thereon	1,349,338	1,172,224
Costs and estimated earnings on uncompleted construction contracts	11,234,530	9,828,866
Less: billings to date	11,641,082	10,188,023
Net billings in excess of costs	$ (406,552)	$ (359,157)

Revenue from Contracts with C_7

Revenue from Contracts with Customers - Schedule of Revenue, Remaining Performance Obligation (Details) $ in Thousands	Dec. 31, 2019USD ($)
Schedule of Remaining Performance Obligations [Line Items]
Remaining performance obligations	$ 4,036,364
Remaining performance obligations, percent	100.00%
UNITED STATES
Schedule of Remaining Performance Obligations [Line Items]
Remaining performance obligations	$ 3,912,188
Remaining performance obligations, percent	97.00%
UNITED STATES | United States Electrical Construction And Facilities Services
Schedule of Remaining Performance Obligations [Line Items]
Remaining performance obligations	$ 1,036,216
Remaining performance obligations, percent	26.00%
UNITED STATES | United States Mechanical Construction And Facilities Services
Schedule of Remaining Performance Obligations [Line Items]
Remaining performance obligations	$ 2,229,090
Remaining performance obligations, percent	55.00%
UNITED STATES | United States Building Services
Schedule of Remaining Performance Obligations [Line Items]
Remaining performance obligations	$ 542,269
Remaining performance obligations, percent	13.00%
UNITED STATES | United States Industrial Services
Schedule of Remaining Performance Obligations [Line Items]
Remaining performance obligations	$ 104,613
Remaining performance obligations, percent	3.00%
UNITED KINGDOM | United Kingdom Building Services
Schedule of Remaining Performance Obligations [Line Items]
Remaining performance obligations	$ 124,176
Remaining performance obligations, percent	3.00%

Revenue from Contracts with C_8

Revenue from Contracts with Customers - Schedule of Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Details) $ in Thousands	Dec. 31, 2019USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 4,036,364
UNITED STATES
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	3,912,188
UNITED STATES | United States Electrical Construction And Facilities Services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	1,036,216
UNITED STATES | United States Mechanical Construction And Facilities Services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	2,229,090
UNITED STATES | United States Building Services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	542,269
UNITED STATES | United States Industrial Services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	104,613
UNITED KINGDOM | United Kingdom Building Services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 124,176
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Remaining performance obligations	$ 3,384,844
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01 | UNITED STATES
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Remaining performance obligations	$ 3,301,286
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01 | UNITED STATES | United States Electrical Construction And Facilities Services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Remaining performance obligations	$ 861,268
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01 | UNITED STATES | United States Mechanical Construction And Facilities Services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Remaining performance obligations	$ 1,802,865
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01 | UNITED STATES | United States Building Services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Remaining performance obligations	$ 532,540
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01 | UNITED STATES | United States Industrial Services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Remaining performance obligations	$ 104,613
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01 | UNITED KINGDOM | United Kingdom Building Services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Remaining performance obligations	$ 83,558
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period
Remaining performance obligations	$ 651,520
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01 | UNITED STATES
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period
Remaining performance obligations	$ 610,902
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01 | UNITED STATES | United States Electrical Construction And Facilities Services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period
Remaining performance obligations	$ 174,948
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01 | UNITED STATES | United States Mechanical Construction And Facilities Services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period
Remaining performance obligations	$ 426,225
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01 | UNITED STATES | United States Building Services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period
Remaining performance obligations	$ 9,729
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01 | UNITED STATES | United States Industrial Services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period
Remaining performance obligations	$ 0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01 | UNITED KINGDOM | United Kingdom Building Services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period
Remaining performance obligations	$ 40,618

Acquisitions Of Businesses (Det

Acquisitions Of Businesses (Details) $ in Thousands	Nov. 01, 2019USD ($)Company	Oct. 31, 2019Company	Sep. 16, 2019Company	Aug. 01, 2019Company	May 10, 2019Company	Apr. 01, 2019Company	Jan. 04, 2019Company	Nov. 01, 2018Company	Oct. 02, 2018Company	May 03, 2018Company	Apr. 04, 2018Company	Nov. 01, 2017Company	Mar. 01, 2017Company	Jan. 04, 2017Company	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Business Acquisition [Line Items]
Goodwill															$ 1,063,911	$ 990,887	$ 964,893
Amortization periods															8 years 6 months
Number of businesses acquired | Company	1	1	1	1	1	1	1	1	1	1	1	1	1	1
BKI [Member]
Business Acquisition [Line Items]
Business acquisition, percentage acquired	100.00%
Purchase price	$ 220,000
Working capital acquired	29,800
Other net assets	4,900
Goodwill	43,600
Identifiable intangible assets	$ 141,700
Amortization periods															10 years 6 months
2019 Acquisitions
Business Acquisition [Line Items]
Purchase price															$ 85,300
Working capital acquired															25,300
Other net assets															1,300
Goodwill															29,100
Identifiable intangible assets															$ 29,600
2018 Acquisitions
Business Acquisition [Line Items]
Purchase price																71,600
Working capital acquired																8,700
Goodwill																26,300
Identifiable intangible assets																$ 36,600
2017 Acquisitions
Business Acquisition [Line Items]
Purchase price																	111,900
Working capital acquired																	12,300
Other net assets																	2,300
Goodwill																	40,700
Identifiable intangible assets																	$ 56,600

Disposition Of Assets (Componen

Disposition Of Assets (Components Of The Results Of Discontinued Operations For The UK Construction Operations) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Loss from discontinued operation, net of income taxes									$ 0	$ (2,345)	$ (857)
Diluted loss per share from discontinued operation (in US dollars per share)	$ 0	$ 0	$ 0	$ 0	$ (0.02)	$ (0.01)	$ 0	$ 0	$ 0	$ (0.04)	$ (0.01)
United Kingdom Construction
Income Statement [Abstract]
Revenues										$ 0	$ 863
Loss from discontinued operation, net of income taxes										$ (2,345)	$ (857)
Diluted loss per share from discontinued operation (in US dollars per share)										$ (0.04)	$ (0.01)
Discontinued Operations [Member] | UNITED KINGDOM | United Kingdom Construction
Income Statement [Abstract]
Current liabilities	$ 0				$ 3,700				$ 0	$ 3,700

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Numerator
Income from continuing operations attributable to EMCOR Group, Inc. common stockholders (in US dollars)									$ 325,140	$ 285,876	$ 228,053
Loss from discontinued operation, net of income taxes (in US dollars)									0	(2,345)	(857)
Net income attributable to EMCOR Group, Inc. (in US dollars)	$ 86,924	$ 81,834	$ 83,972	$ 72,410	$ 77,968	$ 79,373	$ 70,816	$ 55,374	$ 325,140	$ 283,531	$ 227,196
Denominator
Weighted average shares outstanding used to compute basic earnings (loss) per common share (in shares)									56,208,280	58,112,838	59,254,256
Effect of dilutive securities-Share-based awards (in shares)									311,001	330,629	364,713
Shares used to compute diluted earnings (loss) per common share (in shares)									56,519,281	58,443,467	59,618,969
Basic earnings (loss) per common share:
From continuing operations attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	$ 1.54	$ 1.46	$ 1.49	$ 1.29	$ 1.39	$ 1.37	$ 1.22	$ 0.95	$ 5.78	$ 4.92	$ 3.85
From discontinued operation (in US dollars per share)	0	0	0	0	(0.02)	(0.01)	0	0	0	(0.04)	(0.01)
Net income attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	1.54	1.46	1.49	1.29	1.37	1.36	1.22	0.95	5.78	4.88	3.84
Diluted earnings (loss) per common share:
From continuing operations attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	1.54	1.45	1.49	1.28	1.38	1.36	1.21	0.94	5.75	4.89	3.83
From discontinued operation (in US dollars per share)	0	0	0	0	(0.02)	(0.01)	0	0	0	(0.04)	(0.01)
Net income attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	$ 1.54	$ 1.45	$ 1.49	$ 1.28	$ 1.36	$ 1.35	$ 1.21	$ 0.94	$ 5.75	$ 4.85	$ 3.82

Earnings Per Share Antidilutive

Earnings Per Share Antidilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	4,800	550	2,700

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Raw materials and construction materials	$ 31,365	$ 30,006
Work in process	9,081	12,315
Inventories	$ 40,446	$ 42,321

Property, Plant and Equipment_2

Property, Plant and Equipment (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		$ 485,107	$ 440,994
Accumulated depreciation and amortization		(328,920)	(306,643)
Property, plant and equipment, net		156,187	134,351
Depreciation and amortization		43,945	38,472	$ 39,915
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		166,087	151,339
Vehicles
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		59,116	58,205
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		22,123	20,655
Computer hardware/software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		104,916	98,415
Land, buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		113,020	97,937
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		10,236	14,443
Finance lease right-of-use assets (1)
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	[1]	$ 9,609	$ 0
[1]	Finance lease right-of-use assets are recorded net of accumulated amortization. Prior to the adoption of ASC 842 on January 1, 2019, assets under capital leases were recorded as machinery and equipment or computer hardware/software.

Goodwill and Identifiable Int_3

Goodwill and Identifiable Intangible Assets - Narrative (Details) - USD ($)	Oct. 01, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill and Intangible Assets[Line Items]
Goodwill		$ 1,063,911,000	$ 990,887,000	$ 964,893,000
Goodwill acquired		72,700,000	26,300,000
Non-cash goodwill impairment charge		0	0	57,500,000
Non-cash expense for impairment of identifiable intangible assets		0	907,000	57,819,000
Non-cash impairment charge of finite-lived intangible assets		0	900,000	0
Goodwill, accumulated impairment loss				268,100,000
Indefinite-lived intangible asset acquired		$ 171,300,000	36,600,000
Amortization periods		8 years 6 months
Amortization of identifiable intangible assets		$ 48,142,000	42,443,000	48,594,000
Domestic Segments
Goodwill and Intangible Assets[Line Items]
Perpetual growth rate used for annual testing	2.70%
Domestic Construction
Goodwill and Intangible Assets[Line Items]
Weighted average cost of capital used in annual testing for impairment	9.50%
United States Electrical Construction And Facilities Services
Goodwill and Intangible Assets[Line Items]
Goodwill		$ 142,545,000	133,207,000	125,707,000
Goodwill allocated		13.40%
Effect of 50 Basis Point Increase in the Weighted Average Costs of Capital		$ 108,800,000
Effect of 50 Basis Point Decrease in the Perpetual Growth Rate		61,400,000
United States Mechanical Construction And Facilities Services
Goodwill and Intangible Assets[Line Items]
Goodwill		$ 299,220,000	256,321,000	256,265,000
Goodwill allocated		28.10%
Effect of 50 Basis Point Increase in the Weighted Average Costs of Capital		$ 156,700,000
Effect of 50 Basis Point Decrease in the Perpetual Growth Rate		90,500,000
United States Building Services
Goodwill and Intangible Assets[Line Items]
Goodwill		$ 289,158,000	274,171,000	255,733,000
Goodwill allocated		27.20%
Weighted average cost of capital used in annual testing for impairment	9.10%
Effect of 50 Basis Point Increase in the Weighted Average Costs of Capital		$ 98,000,000
Effect of 50 Basis Point Decrease in the Perpetual Growth Rate		55,700,000
Goodwill, accumulated impairment loss				139,500,000
United States Industrial Services
Goodwill and Intangible Assets[Line Items]
Goodwill		$ 332,988,000	327,188,000	327,188,000
Goodwill allocated		31.30%
Weighted average cost of capital used in annual testing for impairment	10.50%
Effect of 50 Basis Point Increase in the Weighted Average Costs of Capital		$ 40,300,000
Effect of 50 Basis Point Decrease in the Perpetual Growth Rate		$ 20,500,000
Goodwill, accumulated impairment loss				128,600,000
Contract backlog
Goodwill and Intangible Assets[Line Items]
Amortization periods		9 months
Developed technology/Vendor network
Goodwill and Intangible Assets[Line Items]
Amortization periods		7 years 6 months
Customer relationships
Goodwill and Intangible Assets[Line Items]
Amortization periods		8 years 9 months
Trade names (amortized)
Goodwill and Intangible Assets[Line Items]
Amortization periods		10 years 9 months
Trade names (unamortized)
Goodwill and Intangible Assets[Line Items]
Non-cash expense for impairment of identifiable intangible assets		$ 0	$ 0	$ 300,000

Goodwill and Identifiable Int_4

Goodwill and Identifiable Intangible Assets - Schedule of Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Goodwill, Beginning balance	$ 990,887	$ 964,893
Acquisitions, sales and purchase price adjustments	73,024	25,994
Goodwill, intersegment transfers	0
Goodwill, Ending balance	1,063,911	990,887
United States electrical construction and facilities services segment
Goodwill [Roll Forward]
Goodwill, Beginning balance	133,207	125,707
Acquisitions, sales and purchase price adjustments	9,338	7,500
Goodwill, intersegment transfers	0
Goodwill, Ending balance	142,545	133,207
United States Mechanical Construction And Facilities Services
Goodwill [Roll Forward]
Goodwill, Beginning balance	256,321	256,265
Acquisitions, sales and purchase price adjustments	48,699	56
Goodwill, intersegment transfers	(5,800)
Goodwill, Ending balance	299,220	256,321
United States Building Services
Goodwill [Roll Forward]
Goodwill, Beginning balance	274,171	255,733
Acquisitions, sales and purchase price adjustments	14,987	18,438
Goodwill, intersegment transfers	0
Goodwill, Ending balance	289,158	274,171
United States Industrial Services
Goodwill [Roll Forward]
Goodwill, Beginning balance	327,188	327,188
Acquisitions, sales and purchase price adjustments	0	0
Goodwill, intersegment transfers	5,800
Goodwill, Ending balance	$ 332,988	$ 327,188

Goodwill and Identifiable Int_5

Goodwill and Identifiable Intangible Assets - Schedule of Finite-lived and Indefinite-lived Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Accumulated Amortization	$ (421,238)	$ (373,096)
Total	412,237
Gross Carrying Amount, Trade names (unamortized)	251,440	209,840
Accumulated Impairment Charge, Trade names (unamortized)	(52,233)	(52,233)
Total, Trade names (unamortized)	199,207	157,607
Gross Carrying Amount, Total	1,089,749	918,449
Accumulated Impairment Charge, Total	(57,067)	(57,067)
Total	611,444	488,286
Contract backlog
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount	66,745	58,945
Accumulated Amortization	(61,651)	(56,812)
Accumulated Impairment Charge	0	0
Total	5,094	2,133
Developed technology/Vendor network
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount	95,661	95,661
Accumulated Amortization	(60,156)	(55,318)
Accumulated Impairment Charge	0	0
Total	35,505	40,343
Customer relationships
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount	644,755	522,855
Accumulated Amortization	(277,601)	(240,073)
Accumulated Impairment Charge	(4,834)	(4,834)
Total	362,320	277,948
Trade names (amortized)
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount	31,148	31,148
Accumulated Amortization	(21,830)	(20,893)
Accumulated Impairment Charge	0	0
Total	$ 9,318	$ 10,255

Goodwill and Identifiable Int_6

Goodwill and Identifiable Intangible Assets - Schedule of Expected Amortization Expense (Details) $ in Thousands	Dec. 31, 2019USD ($)
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2020	$ 56,680
2021	50,792
2022	48,589
2023	47,650
2024	47,300
Thereafter	161,226
Total	$ 412,237

Debt - Narrative (Details)

Debt - Narrative (Details) - USD ($)	Aug. 03, 2016	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 30, 2016
Line of Credit Facility [Line Items]
Repayments of long-term debt (in US dollars)				$ 15,198,000	$ 15,235,000	$ 15,202,000
Letters of credit outstanding (in US dollars)				109,000,000	109,000,000
Borrowings under revolving credit facility (in US dollars)				$ 50,000,000	25,000,000
2016 Credit Agreement
Line of Credit Facility [Line Items]
Credit agreement, initiation date	Aug. 3, 2016
Expiration date of credit agreement				Aug. 3, 2021
Interest rate description				Borrowings under the 2016 Credit Agreement bear interest at (1) a base rate plus a margin of 0.00% to 0.75%, based on certain financial tests, or (2) United States dollar LIBOR (1.80% at December 31, 2019) plus 1.00% to 1.75%, based on certain financial tests. The base rate is determined by the greater of (a) the prime commercial lending rate announced by Bank of Montreal from time to time (4.75% at December 31, 2019), (b) the federal funds effective rate, plus ½ of 1.00%, (c) the daily one month LIBOR rate, plus 1.00%, or (d) 0.00%. The interest rate in effect at December 31, 2019 was 2.80%. Fees for letters of credit issued under the 2016 Revolving Credit Facility range from 1.00% to 1.75% of the respective face amounts of outstanding letters of credit and are computed based on certain financial tests.
Interest rate				2.80%
2016 Term Loan
Line of Credit Facility [Line Items]
Term Loan (in US dollars)	$ 400,000,000			$ 254,431,000	269,620,000
Periodic principal payments on term loan (in US dollars)		$ 3,800,000	$ 5,000,000				$ 5,000,000
Term loan, annual principal payments (in US dollars)								$ 100,000,000
Repayments of long-term debt (in US dollars)							$ 95,000,000
Base Rate | Minimum | 2016 Credit Agreement
Line of Credit Facility [Line Items]
Basis spread on variable rate				0.00%
Base Rate | Maximum | 2016 Credit Agreement
Line of Credit Facility [Line Items]
Basis spread on variable rate				0.75%
Prime Rate, Bank of Montreal | 2016 Credit Agreement
Line of Credit Facility [Line Items]
Commercial lending rate				4.75%
Credit Agreement Base Rate, Daily One Month LIBOR Rate | 2016 Credit Agreement
Line of Credit Facility [Line Items]
Basis spread on variable rate				1.00%
London Interbank Offered Rate (LIBOR) | 2016 Credit Agreement
Line of Credit Facility [Line Items]
Commercial lending rate				1.80%
London Interbank Offered Rate (LIBOR) | Minimum | 2016 Credit Agreement
Line of Credit Facility [Line Items]
Basis spread on variable rate				1.00%
London Interbank Offered Rate (LIBOR) | Maximum | 2016 Credit Agreement
Line of Credit Facility [Line Items]
Basis spread on variable rate				1.75%
Credit Agreeement Base Rate, Federal Funds Rate | 2016 Credit Agreement
Line of Credit Facility [Line Items]
Basis spread on variable rate				0.50%
Credit Agreement, 0% Base Rate | 2016 Credit Agreement
Line of Credit Facility [Line Items]
Commercial lending rate				0.00%
Revolving Credit Facility | 2016 Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit facility maximum borrowing capacity (in US dollars)	$ 900,000,000
Increase in borrowing capacity (in US dollars)				$ 1,300,000,000
Letters of credit maximum borrowing capacity (in US dollars)				$ 300,000,000
Commitment fee percentage of unused amount				0.15%
Borrowings under revolving credit facility (in US dollars)				$ 50,000,000	$ 25,000,000
Revolving Credit Facility | Minimum | 2016 Revolving Credit Facility
Line of Credit Facility [Line Items]
Commitment fee percentage of unused amount				0.15%
Letter of credit fees				1.00%
Revolving Credit Facility | Maximum | 2016 Revolving Credit Facility
Line of Credit Facility [Line Items]
Commitment fee percentage of unused amount				0.30%
Letter of credit fees				1.75%

Debt - Schedule Of Debt (Detail

Debt - Schedule Of Debt (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018	Aug. 03, 2016
Debt Instrument [Line Items]
Revolving credit facility	$ 50,000,000	$ 25,000,000
Unamortized debt issuance costs	(1,879,000)	(3,065,000)
Finance lease liabilities	9,679,000	4,213,000
Other	0	9,000
Total debt	312,231,000	295,777,000
Less: current maturities	18,092,000	16,013,000
Total long-term debt	294,139,000	279,764,000
2016 Term Loan
Debt Instrument [Line Items]
Term Loan	254,431,000	269,620,000	$ 400,000,000
Revolving Credit Facility | 2016 Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility	$ 50,000,000	$ 25,000,000

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule Of Assets And Liabilities Carried At Fair Value Measured On A Recurring Basis) (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Restricted cash		$ 1,100	$ 2,300	$ 2,000	$ 2,000
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents		358,818	363,907
Restricted cash		1,102	2,307
Deferred compensation plan assets		30,295	23,124
Total		390,215	389,338
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents	[1]	358,818	363,907
Restricted cash	[2]	1,102	2,307
Deferred compensation plan assets	[3]	30,295	23,124
Total		390,215	389,338
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents	[1]	0	0
Restricted cash	[2]	0	0
Deferred compensation plan assets	[3]	0	0
Total		0	0
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents	[1]	0	0
Restricted cash	[2]	0	0
Deferred compensation plan assets	[3]	0	0
Total		0	0
Money Market Funds | Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents		$ 164,000	$ 161,300
[1]	Cash and cash equivalents consist of deposit accounts and money market funds with original maturity dates of three months or less, which are Level 1 assets. At December 31, 2019 and 2018 , we had $164.0 million and $161.3 million , respectively, in money market funds.
[2]	Restricted cash is classified as “Prepaid expenses and other” in the Consolidated Balance Sheets. Restricted cash primarily represents cash held in account for use on customer contracts.
[3]	Deferred compensation plan assets are classified as “Other assets” in the Consolidated Balance Sheets.

Income Taxes (Details)

Income Taxes (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Federal income tax rate, percent		21.00%	35.00%
Tax Act income tax benefit			$ 39,300,000
Income tax provision	$ 125,749,000	$ 109,106,000	$ 90,699,000
Actual income tax rates	27.90%	27.60%	28.50%
Income tax expense, foreign minimum tax	$ 100,000	$ 600,000
Cash and cash equivalents	358,818,000	363,907,000
Unrecognized income tax benefits	0	0
Deferred tax liabilities, net	71,746,000	70,848,000
Valuation allowance for deferred tax assets	3,463,000	3,855,000
Trading losses	0	4,200,000
Other Assets
Operating Loss Carryforwards [Line Items]
Deferred tax liabilities, net	3,400,000	4,700,000
Other Long-Term Obligations
Operating Loss Carryforwards [Line Items]
Deferred tax liabilities, net	75,200,000	$ 75,500,000
Non-US [Member] | Subsidiaries [Member]
Operating Loss Carryforwards [Line Items]
Undistributed earnings of foreign subsidiaries	69,800,000
Cash and cash equivalents	$ 67,700,000

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income before Income Tax From Continuing Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
United States	$ 430,253	$ 375,408	$ 303,854
Foreign	20,636	19,620	14,895
Income from continuing operations before income taxes	$ 450,889	$ 395,028	$ 318,749

Income Taxes - Schedule of In_2

Income Taxes - Schedule of Income Tax Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Federal provision	$ 89,264	$ 75,405	$ 120,317
State and local provisions	31,099	28,063	23,496
Foreign provision	3,685	1,389	244
Current income tax expense	124,048	104,857	144,057
Deferred	1,701	4,249	(53,358)
Income tax provision	$ 125,749	$ 109,106	$ 90,699

Income Taxes - Schedule of U.S.

Income Taxes - Schedule of U.S. Statutory Income Tax Rates From Continuing Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Federal income taxes at the statutory rate	$ 94,687	$ 82,946	$ 111,562
State and local income taxes, net of federal tax benefits	24,904	21,827	15,736
State tax reserves	0	(7)	(2,543)
Permanent differences	7,149	6,584	4,916
Domestic manufacturing deduction	0	0	(10,387)
Excess tax benefit from share-based compensation	(733)	(1,227)	(1,341)
Goodwill impairment	0	0	17,055
Foreign income taxes (including UK statutory rate changes)	(170)	70	(2,586)
Impact of federal rate change on net deferred tax liabilities	0	0	(39,343)
Federal tax reserves	0	(67)	(1,247)
Other	(88)	(1,020)	(1,123)
Income tax provision	$ 125,749	$ 109,106	$ 90,699

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019		Dec. 31, 2018
Deferred income tax assets:
Insurance liabilities	$ 47,022		$ 44,192
Pension liability	2,733		3,204
Operating lease liabilities (1)	68,158	[1]	0
Deferred compensation	32,685		29,300
Other (including liabilities and reserves)	25,647		27,400
Total deferred income tax assets	176,245		104,096
Valuation allowance for deferred tax assets	(3,463)		(3,855)
Net deferred income tax assets	172,782		100,241
Deferred income tax liabilities:
Goodwill and identifiable intangible assets	(156,604)		(152,761)
Operating lease right-of-use assets (1)	(65,090)	[1]	0
Depreciation of property, plant and equipment	(18,622)		(14,904)
Other	(4,212)		(3,424)
Total deferred income tax liabilities	(244,528)		(171,089)
Net deferred income tax liabilities	$ (71,746)		$ (70,848)
[1]	As discussed in Note 2 - Summary of Significant Accounting Policies of the notes to consolidated financial statements, on January 1, 2019, we adopted the accounting pronouncement issued by the Financial Accounting Standards Board (“FASB”), which required lessees to record right-of-use assets and corresponding lease liabilities on the balance sheet for most leases. We adopted this pronouncement utilizing the transition practical expedient added by the FASB, which eliminated the requirement that entities apply the new lease standard to the comparative periods presented in the year of adoption.

Common Stock (Details)

Common Stock (Details) - USD ($)	3 Months Ended	12 Months Ended			99 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Sep. 26, 2011
Equity, Class of Treasury Stock [Line Items]
Common stock, outstanding (in shares)	56,219,831	56,219,831	55,983,763		56,219,831
Dividend paid (in dollars per share)	$ 0.08
Stock repurchased (in US dollars)			$ 216,244,000	$ 90,821,000
Common Stock
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased (in shares)		0			15,900,000
Stock repurchased (in US dollars)				$ 10,000	$ 791,500,000
Remaining authorized repurchase amount (in US dollars)	$ 158,500,000	$ 158,500,000			158,500,000
Common Stock | RepurchaseProgramSept262011
Equity, Class of Treasury Stock [Line Items]
Stock repurchase, authorized amount (in US dollars)						$ 100,000,000
Common Stock | RepurchaseProgramSep2011toDec2019
Equity, Class of Treasury Stock [Line Items]
Stock repurchase, authorized amount (in US dollars)	$ 950,000,000	$ 950,000,000			$ 950,000,000

Share-Based Compensation Plan_2

Share-Based Compensation Plans - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized under employee stock purchase plan (in shares)	3,250,000
Shares available for grant or issuance under share-based compensation plans (in shares)	1,160,086
Compensation expense to be recognized	$ 8,700,000
Maximum vesting period	3 years
Tax benefit from exercise of stock options	$ 2,600,000	$ 3,600,000	$ 3,900,000
Excess tax benefit from share-based compensation	984,000	1,646,000	1,616,000
Total intrinsic value of options exercised	$ 1,200,000	$ 2,700,000	$ 2,300,000
Options that were exercisable (in shares)	20,000	40,000	93,000
Weighted average exercise price of exercisable options (in dollars per share)	$ 24.48	$ 24.48	$ 24.48
Total intrinsic value of options outstanding and exercisable	$ 1,200,000	$ 1,400,000	$ 5,300,000
Awards of Shares and Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 11,400,000	$ 11,000,000	$ 9,900,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (in shares)	0	0	0
Compensation expense	$ 0	$ 0	$ 0
Options outstanding	20,000	40,000	93,000	143,000
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested, but issuance deferred (in shares)	72,310
Issuance deferral period	5 years
Employee Stock Purchase Plan (in shares)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized under employee stock purchase plan (in shares)	3,000,000

Share-Based Compensation Plan_3

Share-Based Compensation Plans - Schedule of activity of stock options and awards of shares and stock units (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares, Beginning Balance	40,000	93,000	143,000
Weighted Average Price, Beginning Balance (in dollars per share)	$ 24.48	$ 24.48	$ 23.06
Shares, Granted	0	0	0
Weighted Average Price, Granted (in dollars per share)	$ 0	$ 0	$ 0
Shares, Expired	0	0	0
Weighted Average Price, Expired (in dollars per share)	$ 0	$ 0	$ 0
Shares, Exercised	(20,000)	(53,000)	(50,000)
Weighted Average Price, Exercised (in dollars per share)	$ 24.48	$ 24.48	$ 20.42
Shares, Ending Balance	20,000	40,000	93,000
Weighted Average Price, Ending Balance (in dollars per share)	$ 24.48	$ 24.48	$ 24.48
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Shares, Beginning Balance	476,586	508,872	492,288
Weighted Average Price, Beginning Balance (in dollars per share)	$ 63.52	$ 54.13	$ 44.93
Shares, Granted	169,766	135,259	198,179
Weighted Average Price, Granted (in dollars per share)	$ 64.34	$ 80.37	$ 68.33
Shares, Forfeited	(2,545)	(1,250)	(1,200)
Weighted Average Price, Forfeited (in dollars per share)	$ 71.88	$ 71.27	$ 60.68
Shares, Vested	(226,229)	(166,295)	(180,395)
Weighted Average Price, Vested (in dollars per share)	$ 51.64	$ 48.44	$ 44.57
Shares, Ending Balance	417,578	476,586	508,872
Weighted Average Price, Ending Balance (in dollars per share)	$ 70.24	$ 63.52	$ 54.13

Share-Based Compensation Plan_4

Share-Based Compensation Plans - Summary of information about stock options (Details) - $24.48	12 Months Ended
	Dec. 31, 2019$ / sharesshares
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Range	$ 24.48
Range of Exercise Prices, Upper Range	$ 24.48
Stock Options Outstanding and Exercisable, Number (in shares) | shares	20,000
Stock Options Outstanding and Exercisable, Weighted Average Remaining Life	5 months 12 days
Stock Options Outstanding and Exercisable, Weighted Average Exercise Price	$ 24.48

Defined Benefit Plans - Narrati

Defined Benefit Plans - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)plan	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Estimated unrecognized loss that will be amortized from AOCI, net of income taxes	$ 300
Number of plans | plan	3
Benefit obligation	$ 9,200	$ 8,500
Fair value of plan assets	$ 5,700	$ 4,900
Annual rate of return on plan assets	7.00%	7.00%
Estimated future benefit payments	$ 600
Net periodic pension cost (income)	$ 300	$ 300	$ 300
Minimum | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.00%	4.00%
Maximum | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.00%	4.25%
United Kingdom Subsidiary | UK Plan
Defined Benefit Plan Disclosure [Line Items]
Underfunded status of UK Plan	$ 15,765	$ 17,582
Annual rate of inflation	2.00%	2.10%
Average life expectancy	25 years
Estimated unrecognized loss that will be amortized from AOCI, net of income taxes	$ 2,000
Future estimated employer contributions to be paid next year	4,800
Benefit obligation	322,766	$ 281,776	332,618
Fair value of plan assets	$ 307,001	$ 264,194	$ 295,968
Discount rate	2.10%	2.90%
Annual rate of return on plan assets	4.90%	5.00%	5.30%
Net periodic pension cost (income)	$ (1,862)	$ (3,082)	$ (1,944)
Selling, General and Administrative Expenses | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Reclassification adjustment from AOCI, net of income taxes	200	200	200
Selling, General and Administrative Expenses | United Kingdom Subsidiary | UK Plan
Defined Benefit Plan Disclosure [Line Items]
Reclassification adjustment from AOCI, net of income taxes	1,900	2,100	$ 2,300
Other Noncurrent Liabilities | United Kingdom Subsidiary | UK Plan
Defined Benefit Plan Disclosure [Line Items]
Underfunded status of UK Plan	$ 15,800	$ 17,600

Retirement Plans - Schedule of

Retirement Plans - Schedule of Changes in Benefit Obligations and Assets (Details) - United Kingdom Subsidiary - UK Plan - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	$ 281,776	$ 332,618
Interest cost	7,961	8,085	$ 8,622
Actuarial loss (gain)	32,866	(27,755)
Benefits paid	(12,059)	(14,318)
Foreign currency exchange rate changes	12,222	(16,854)
Benefit obligation at end of year	322,766	281,776	332,618
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	264,194	295,968
Actual return on plan assets	38,808	(6,489)
Employer contributions	4,428	4,742
Benefits paid	(12,059)	(14,318)
Foreign currency exchange rate changes	11,630	(15,709)
Fair value of plan assets at end of year	307,001	264,194	$ 295,968
Funded status at end of year	$ (15,765)	$ (17,582)

Retirement Plans - Schedule o_2

Retirement Plans - Schedule of Net Periodic Benefit Cost Not yet Recognized (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
United Kingdom Subsidiary | UK Plan
Defined Benefit Plan Disclosure [Line Items]
Unrecognized losses	$ 94,211	$ 86,768

Retirement Plans - Schedule o_3

Retirement Plans - Schedule of Weighted Average Assumptions Used To Calculate Benefit Obligations (Details)	Dec. 31, 2019	Dec. 31, 2018
United Kingdom Subsidiary | UK Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.10%	2.90%

Retirement Plans - Schedule o_4

Retirement Plans - Schedule of Weighted Average Assumptions Used To Calculate Net Periodic Pension Costs (Details) - United Kingdom Subsidiary - UK Plan	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.90%	2.50%	2.70%
Annual rate of return on plan assets	4.90%	5.00%	5.30%

Components Of Net Periodic Pens

Components Of Net Periodic Pension Benefit Cost (Details) - United Kingdom Subsidiary - UK Plan - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 7,961	$ 8,085	$ 8,622
Expected return on plan assets	(12,165)	(13,797)	(13,508)
Amortization of unrecognized loss	2,342	2,630	2,942
Net periodic pension cost (income)	$ (1,862)	$ (3,082)	$ (1,944)

Retirement Plans - Schedule o_5

Retirement Plans - Schedule of Weighted Average Assets Allocation and Weighted Average Target Allocation (Details) - United Kingdom Subsidiary - UK Plan	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Target Asset Allocation	100.00%
Asset Allocation	100.00%	100.00%
Debt
Defined Benefit Plan Disclosure [Line Items]
Target Asset Allocation	65.00%
Asset Allocation	70.60%	71.20%
Equity
Defined Benefit Plan Disclosure [Line Items]
Target Asset Allocation	15.00%
Asset Allocation	10.50%	13.40%
Cash
Defined Benefit Plan Disclosure [Line Items]
Target Asset Allocation	10.00%
Asset Allocation	10.50%	6.10%
Real estate
Defined Benefit Plan Disclosure [Line Items]
Target Asset Allocation	10.00%
Asset Allocation	8.40%	9.30%

Retirement Plans - Schedule o_6

Retirement Plans - Schedule of Plan Assets Fair Value Hierarchy (Details) - United Kingdom Subsidiary - UK Plan - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		$ 307,001	$ 264,194	$ 295,968
Corporate debt funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		64,314	37,703
Corporate debt funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0	0
Corporate debt funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		64,314	37,703
Corporate debt funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0	0
Government bond funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		49,164	52,445
Government bond funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0	0
Government bond funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		49,164	52,445
Government bond funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0	0
Equity funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		32,356	35,425
Equity funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0	0
Equity funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		32,356	35,425
Equity funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0	0
Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		32,240	16,097
Cash | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		32,240	16,097
Cash | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0	0
Cash | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0	0
Total plan assets in fair value hierarchy
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		178,074	141,670
Total plan assets in fair value hierarchy | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		32,240	16,097
Total plan assets in fair value hierarchy | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		145,834	125,573
Total plan assets in fair value hierarchy | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0	0
Debt funds | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	[1]	103,188	98,077
Real estate funds | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	[1]	$ 25,739	$ 24,447
[1]	Certain investments measured using NAV as a practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in the table are intended to permit reconciliation of the fair value hierarchy to the total fair value of plan assets.

Retirement Plans - Schedule o_7

Retirement Plans - Schedule of Expected Benefit Payments (Details) - United Kingdom Subsidiary - UK Plan $ in Thousands	Dec. 31, 2019USD ($)
Defined Benefit Plan Disclosure [Line Items]
2020	$ 12,887
2021	13,240
2022	13,603
2023	13,976
2024	14,358
Succeeding five years	$ 77,912

Retirement Plans - Schedule o_8

Retirement Plans - Schedule of Accumulated Benefit Obligation in Excess of Fair Value of Plan Assets (Details) - United Kingdom Subsidiary - UK Plan - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 322,766	$ 281,776
Accumulated benefit obligation	322,766	281,776
Fair value of plan assets	$ 307,001	$ 264,194

Multiemployer Plans - Narrative

Multiemployer Plans - Narrative (Details)	12 Months Ended
	Dec. 31, 2019USD ($)plan	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Multiemployer Plans [Line Items]
Withdrawal liability	$ 0	$ 0	$ 0
Minimum | Multiemployer Plans, Pension
Multiemployer Plans [Line Items]
Number of plans | plan	200
UNITED STATES | Multiemployer Plans, Pension | Multiemployer Plan, Plan Information, Available
Multiemployer Plans [Line Items]
Contribution increase due to acquisition	$ 4,800,000
Contributions	215,478,000	190,229,000	179,216,000
UNITED STATES | Multiemployer Plans, Postretirement Benefit | Multiemployer Plan, Plan Information, Not Available
Multiemployer Plans [Line Items]
Contribution increase due to acquisition	11,000,000
Contributions	153,500,000	135,900,000	130,900,000
UNITED STATES | Minimum | Multiemployer Plans, Pension | Multiemployer Plan, Plan Information, Available
Multiemployer Plans [Line Items]
Contributions	2,000,000
UK Plan | Multiemployer Plans, Pension | Multiemployer Plan, Plan Information, Not Available
Multiemployer Plans [Line Items]
Contributions	$ 100,000	$ 100,000	$ 100,000
Multiemployer plans, funded status	At least 80 percent
Red Zone | UNITED STATES | Minimum | Multiemployer Plans, Pension | Multiemployer Plan, Plan Information, Available
Multiemployer Plans [Line Items]
Contributions	$ 500,000
Orange or Yellow Zones | UNITED STATES | Minimum | Multiemployer Plans, Pension | Multiemployer Plan, Plan Information, Available
Multiemployer Plans [Line Items]
Contributions	$ 1,000,000

Retirement Plans - Schedule o_9

Retirement Plans - Schedule of Multiemployer Plans (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Multiemployer Plans [Line Items]
EIN		11-2125338
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension
Multiemployer Plans [Line Items]
Contributions		$ 215,478	$ 190,229	$ 179,216
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | National Electrical Benefit Fund
Multiemployer Plans [Line Items]
EIN		53-0181657
Pension Plan Number		001
PPA Zone Status	[1]	Green	Green
FIP/RP Status		NA
Contributions		$ 16,901	$ 10,700	11,572
Contributions greater than 5%	[2]	false
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | National Automatic Sprinkler Industry Pension Fund
Multiemployer Plans [Line Items]
EIN		52-6054620
Pension Plan Number		001
PPA Zone Status	[1]	Red	Red
FIP/RP Status		Implemented
Contributions		$ 15,924	$ 14,888	14,228
Contributions greater than 5%	[2]	false
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Plumbers & Pipefitters National Pension Fund
Multiemployer Plans [Line Items]
EIN		52-6152779
Pension Plan Number		001
PPA Zone Status	[1]	Yellow	Yellow
FIP/RP Status		Implemented
Contributions		$ 13,821	$ 11,868	12,550
Contributions greater than 5%	[2]	false
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Sheet Metal Workers National Pension Fund
Multiemployer Plans [Line Items]
EIN		52-6112463
Pension Plan Number		001
PPA Zone Status	[1]	Yellow	Yellow
FIP/RP Status		Implemented
Contributions		$ 11,713	$ 10,895	12,895
Contributions greater than 5%	[2]	false
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Pension, Hospitalization & Benefit Plan of the Electrical Industry-Pension Trust Account
Multiemployer Plans [Line Items]
EIN		13-6123601
Pension Plan Number		001
PPA Zone Status	[1]	Green	Green
FIP/RP Status		NA
Contributions		$ 10,075	$ 10,469	9,489
Contributions greater than 5%	[2]	false
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Electrical Workers Local No. 26 Pension Trust Fund
Multiemployer Plans [Line Items]
EIN		52-6117919
Pension Plan Number		001
PPA Zone Status	[1]	Green	Green
FIP/RP Status		NA
Contributions		$ 8,434	$ 5,485	4,441
Contributions greater than 5%	[2]	true
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Plumbers Pipefitters & Mechanical Equipment Service Local Union 392 Pension Plan
Multiemployer Plans [Line Items]
EIN		31-0655223
Pension Plan Number		001
PPA Zone Status	[1]	Red	Red
FIP/RP Status		Implemented
Contributions		$ 6,412	$ 6,047	6,084
Contributions greater than 5%	[2]	true
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Southern California IBEW-NECA Pension Trust Fund
Multiemployer Plans [Line Items]
EIN		95-6392774
Pension Plan Number		001
PPA Zone Status	[1]	Yellow	Yellow
FIP/RP Status		Implemented
Contributions		$ 6,277	$ 5,754	3,669
Contributions greater than 5%	[2]	false
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Central Pension Fund of the IUOE & Participating Employers
Multiemployer Plans [Line Items]
EIN		36-6052390
Pension Plan Number		001
PPA Zone Status	[1]	Green	Green
FIP/RP Status		NA
Contributions		$ 6,253	$ 6,384	6,070
Contributions greater than 5%	[2]	false
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Sheet Metal Workers Pension Plan of Northern California
Multiemployer Plans [Line Items]
EIN		51-6115939
Pension Plan Number		001
PPA Zone Status	[1]	Red	Red
FIP/RP Status		Implemented
Contributions		$ 6,233	$ 5,488	6,023
Contributions greater than 5%	[2]	false
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Arizona Pipe Trades Pension Trust Fund
Multiemployer Plans [Line Items]
EIN		86-6025734
Pension Plan Number		001
PPA Zone Status	[1]	Green	Green
FIP/RP Status		NA
Contributions		$ 6,071	$ 2,640	1,662
Contributions greater than 5%	[2]	true
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Edison Pension Plan
Multiemployer Plans [Line Items]
EIN		93-6061681
Pension Plan Number		001
PPA Zone Status	[1]	Green	Green
FIP/RP Status		NA
Contributions		$ 5,361	$ 3,140	1,628
Contributions greater than 5%	[2]	true
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Pipefitters Union Local 537 Pension Fund
Multiemployer Plans [Line Items]
EIN		51-6030859
Pension Plan Number		001
PPA Zone Status	[1]	Green	Green
FIP/RP Status		NA
Contributions		$ 4,754	$ 6,038	4,057
Contributions greater than 5%	[2]	true
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Heating, Piping & Refrigeration Pension Fund
Multiemployer Plans [Line Items]
EIN		52-1058013
Pension Plan Number		001
PPA Zone Status	[1]	Green	Green
FIP/RP Status		NA
Contributions		$ 4,185	$ 2,619	2,437
Contributions greater than 5%	[2]	false
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | U.A. Local 393 Pension Trust Fund Defined Benefit
Multiemployer Plans [Line Items]
EIN		94-6359772
Pension Plan Number		002
PPA Zone Status	[1]	Green	Green
FIP/RP Status		NA
Contributions		$ 3,858	$ 4,298	1,540
Contributions greater than 5%	[2]	true
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | San Diego Electrical Pension Plan
Multiemployer Plans [Line Items]
EIN		95-6101801
Pension Plan Number		001
PPA Zone Status	[1]	Green	Green
FIP/RP Status		NA
Contributions		$ 3,843	$ 3,008	2,862
Contributions greater than 5%	[2]	true
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Eighth District Electrical Pension Fund
Multiemployer Plans [Line Items]
EIN		84-6100393
Pension Plan Number		001
PPA Zone Status	[1]	Green	Green
FIP/RP Status		NA
Contributions		$ 3,590	$ 3,486	3,786
Contributions greater than 5%	[2]	true
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Southern California Pipe Trades Retirement Fund
Multiemployer Plans [Line Items]
EIN		51-6108443
Pension Plan Number		001
PPA Zone Status	[1]	Green	Green
FIP/RP Status		NA
Contributions		$ 3,274	$ 3,095	3,907
Contributions greater than 5%	[2]	false
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Electrical Contractors Association and Local Union 134, IBEW Joint Pension Trust of Chicago Pension Plan 2
Multiemployer Plans [Line Items]
EIN		51-6030753
Pension Plan Number		002
PPA Zone Status	[1]	Green	Green
FIP/RP Status		NA
Contributions		$ 3,204	$ 4,308	5,537
Contributions greater than 5%	[2]	false
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Northern California Pipe Trades Pension Plan
Multiemployer Plans [Line Items]
EIN		94-3190386
Pension Plan Number		001
PPA Zone Status	[1]	Green	Green
FIP/RP Status		NA
Contributions		$ 3,077	$ 3,104	2,963
Contributions greater than 5%	[2]	false
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | NECA-IBEW Pension Trust Fund
Multiemployer Plans [Line Items]
EIN		51-6029903
Pension Plan Number		001
PPA Zone Status	[1]	Green	Green
FIP/RP Status		NA
Contributions		$ 2,528	$ 2,650	3,060
Contributions greater than 5%	[2]	false
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | U.A. Plumbers Local 24 Pension Fund
Multiemployer Plans [Line Items]
EIN		22-6042823
Pension Plan Number		001
PPA Zone Status	[1]	Green	Green
FIP/RP Status		NA
Contributions		$ 2,460	$ 3,461	3,092
Contributions greater than 5%	[2]	true
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Sheet Metal Workers Pension Plan of Southern California, Arizona & Nevada
Multiemployer Plans [Line Items]
EIN		95-6052257
Pension Plan Number		001
PPA Zone Status	[1]	Yellow	Yellow
FIP/RP Status		Implemented
Contributions		$ 2,423	$ 1,934	3,268
Contributions greater than 5%	[2]	false
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Connecticut Plumbers & Pipefitters Pension Fund
Multiemployer Plans [Line Items]
EIN		06-6050353
Pension Plan Number		001
PPA Zone Status	[1]	Green	Green
FIP/RP Status		NA
Contributions		$ 2,231	$ 2,104	1,988
Contributions greater than 5%	[2]	true
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | U.A. Local 38 Defined Benefit Pension Plan
Multiemployer Plans [Line Items]
EIN		94-1285319
Pension Plan Number		001
PPA Zone Status	[1]	Green	Green
FIP/RP Status		NA
Contributions		$ 2,030	$ 1,551	2,097
Contributions greater than 5%	[2]	false
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Plumbing & Pipe Fitting Local 219 Pension Fund
Multiemployer Plans [Line Items]
EIN		34-6682376
Pension Plan Number		001
PPA Zone Status	[1]	Red	Red
FIP/RP Status		Implemented
Contributions		$ 1,937	$ 2,197	1,335
Contributions greater than 5%	[2]	true
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Boilermaker-Blacksmith National Pension Trust
Multiemployer Plans [Line Items]
EIN		48-6168020
Pension Plan Number		001
PPA Zone Status	[1]	Red	Red
FIP/RP Status		Implemented
Contributions		$ 1,681	$ 1,446	1,083
Contributions greater than 5%	[2]	false
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Plumbers & Pipefitters Local Union No. 502 & 633 Pension Fund
Multiemployer Plans [Line Items]
EIN		61-6078145
Pension Plan Number		001
PPA Zone Status	[1]	Yellow	Yellow
FIP/RP Status		Implemented
Contributions		$ 1,596	$ 1,167	801
Contributions greater than 5%	[2]	false
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Plumbers & Pipefitters Local 162 Pension Fund
Multiemployer Plans [Line Items]
EIN		31-6125999
Pension Plan Number		001
PPA Zone Status	[1]	Yellow	Yellow
FIP/RP Status		Implemented
Contributions		$ 1,124	$ 1,273	801
Contributions greater than 5%	[2]	true
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Steamfitters Local Union No. 420 Pension Plan
Multiemployer Plans [Line Items]
EIN		23-2004424
Pension Plan Number		001
PPA Zone Status	[1]	Red	Red
FIP/RP Status		Implemented
Contributions		$ 641	$ 706	687
Contributions greater than 5%	[2]	false
Multiemployer Plan, Plan Information, Available | UNITED STATES | Multiemployer Plans, Pension | Other Multiemployer Pension Plans
Multiemployer Plans [Line Items]
Contributions		$ 53,567	$ 48,026	$ 43,604
[1]	The zone status represents the most recent available information for the respective MEPP, which may be 2018 or earlier for the 2019 year and 2017 or earlier for the 2018 year.
[2]	This information was obtained from the respective plan’s Form 5500 (“Forms”) for the most current available filing. These dates may not correspond with our fiscal year contributions. The above noted percentages of contributions are based upon disclosures contained in the plans’ Forms. Those Forms, among other things, disclose the names of individual participating employers whose annual contributions account for more than 5% of the aggregate annual amount contributed by all participating employers for a plan year. Accordingly, if the annual contribution of two or more of our subsidiaries each accounted for less than 5% of such contributions, but in the aggregate accounted for in excess of 5% of such contributions, that greater percentage is not available and accordingly is not disclosed.

Defined Contribution Plans - Na

Defined Contribution Plans - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
UNITED STATES
Defined Contribution Plan Disclosure [Line Items]
Expense recognized	$ 32.4	$ 29.8	$ 28.1
Supplemental matching	6.8	6.1	5.5
United Kingdom Subsidiary | UK Plan
Defined Contribution Plan Disclosure [Line Items]
Expense recognized	$ 6.1	$ 4.9	$ 3.9

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)employeecollective_bargaining_agreement	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Loss Contingencies [Line Items]
Number of collective bargaining agreements that are national or regional in scope | collective_bargaining_agreement	2
Restructuring expenses	$ 1,523	$ 2,306	$ 1,577
Restructuring reserve	$ 1,558	1,630	492
Minimum
Loss Contingencies [Line Items]
Number of employees | employee	36,000
Number of collective bargaining agreements between our individual subsidiaries and local unions | collective_bargaining_agreement	400
Surety Bond [Member]
Loss Contingencies [Line Items]
Aggregate estimated exposure	$ 1,200,000
Employee Severance [Member]
Loss Contingencies [Line Items]
Restructuring expenses	$ 1,500	$ 2,300	$ 1,600
Unionized Employees Concentration Risk [Member] | Workforce Subject to Collective Bargaining Arrangements [Member]
Loss Contingencies [Line Items]
Percentage of employees represented by unions	59.00%

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Restructuring Activities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	$ 1,558	$ 1,630	$ 492
Restructuring expenses	1,523	2,306	1,577
Payments for restructuring	(1,595)	(1,168)
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	1,500	2,300	1,600
Corporate, Non-Segment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	701	1,424	0
Restructuring expenses	0	1,424
Payments for restructuring	723	0
UNITED STATES | Operating Segments [Member] | United States Electrical Construction And Facilities Services
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	445	30	452
Restructuring expenses	445	0
Payments for restructuring	(30)	(422)
UNITED STATES | Operating Segments [Member] | United States Building Services
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	412	176	$ 40
Restructuring expenses	1,078	882
Payments for restructuring	$ (842)	$ (746)

Leases (Details)

Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Leases [Abstract]
Rent expense, net of sublease income		$ 191.8	$ 166.5
Sublease rental income	$ 0.5	0.6	0.6
Assets acquired under capital leases		$ 1.1	$ 1.3

Leases - Schedule of Lease Asse

Leases - Schedule of Lease Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentNet
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	eme:CurrentMaturitiesOfLongTermDebtAndFinanceLeaseLiabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	eme:LongTermDebtAndFinanceLeaseLiabilitiesNonCurrent
Assets
Operating lease right-of-use assets	$ 245,471	$ 0
Finance lease right-of-use assets	9,609
Total lease assets	255,080
Current
Operating lease liabilities, current	53,144	0
Finance lease liabilities, current	4,088
Noncurrent
Operating lease liabilities, long-term	204,950	$ 0
Finance lease liabilities, long-term	5,591
Total lease liabilities	$ 267,773

Leases - Schedule of Lease Cost

Leases - Schedule of Lease Costs (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Finance lease expense:
Amortization expense	$ 4,575
Interest expense	427
Operating lease expense	66,650
Short-term lease expense	149,528
Variable lease expense	4,924
Total lease expense	$ 226,104

Leases - Schedule of Lease Term

Leases - Schedule of Lease Term and Discount Rate (Details)	Dec. 31, 2019
Weighted-average remaining lease term:
Operating leases	6 years 8 months 12 days
Finance leases	2 years 10 months 24 days
Weighed-average discount rate:
Operating leases	4.04%
Finance leases	4.16%

Leases - Schedule of Supplement

Leases - Schedule of Supplemental Cash Flow Lease Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
CashPaidForAmountsIncludedInTheMeasurementOfLeaseLiabilities [Abstract]
Operating cash flows used for operating leases	$ 65,757
Operating cash flows used for finance leases	427
Financing cash flows used for finance leases	4,571
Right-of-use assets obtained in exchange for new operating lease liabilities	84,089
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 5,311

Leases - Schedule of Maturity o

Leases - Schedule of Maturity of Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Operating Leases
2020	$ 62,457
2021	50,505
2022	42,155
2023	35,223
2024	26,049
Thereafter	80,661
Total minimum lease payments	297,050
Less: Amount of lease payments representing interest	(38,956)
Present value of future minimum lease payments	258,094
Current portion of lease liabilities	53,144	$ 0
Noncurrent portion of lease liabilities	204,950	0
Finance Leases
2020	4,391
2021	3,039
2022	1,807
2023	743
2024	138
Thereafter	129
Total minimum lease payments	10,247
Less: Amount of lease payments representing interest	(568)
Present value of future minimum lease payments	9,679	$ 4,213
Current portion of lease liabilities	4,088
Noncurrent portion of lease liabilities	$ 5,591

Additional Cash Flow Informat_3

Additional Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash paid during the year for:
Interest	$ 12,683	$ 12,435	$ 11,456
Income taxes	$ 126,169	$ 123,651	$ 130,226

Segment Information (Informatio

Segment Information (Information About Industry Segments And Geographic Areas) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues from unrelated entities	$ 2,403,940,000	$ 2,287,741,000	$ 2,324,202,000	$ 2,158,728,000	$ 2,229,308,000	$ 2,047,049,000	$ 1,953,886,000	$ 1,900,388,000	$ 9,174,611,000	$ 8,130,631,000	$ 7,686,999,000
Total revenues									9,174,611,000	8,130,631,000	7,686,999,000
Operating income (loss)									460,892,000	403,083,000	328,902,000
Restructuring expenses									(1,523,000)	(2,306,000)	(1,577,000)
Impairment loss on goodwill and identifiable intangible assets									0	(907,000)	(57,819,000)
Net periodic pension (cost) income									1,553,000	2,743,000	1,652,000
Interest expense									(13,821,000)	(13,544,000)	(12,770,000)
Interest income									2,265,000	2,746,000	965,000
Income from continuing operations before income taxes									450,889,000	395,028,000	318,749,000
Capital expenditures									48,432,000	43,479,000	34,684,000
Depreciation and amortization of property, plant and equipment									43,945,000	38,472,000	39,915,000
Contract assets	177,830,000				158,243,000				177,830,000	158,243,000	122,621,000
Contract liabilities	623,642,000				552,290,000				623,642,000	552,290,000	524,156,000
Long-lived assets	1,831,542,000				1,613,524,000				1,831,542,000	1,613,524,000	1,587,085,000
Total assets	4,830,358,000				4,088,807,000				4,830,358,000	4,088,807,000	3,965,904,000
Loss on contracts									0
United States electrical construction and facilities services segment | Transportation Sector [Member]
Segment Reporting Information [Line Items]
Loss on contracts										10,000,000
United States Industrial Services
Segment Reporting Information [Line Items]
Settlement of contract claim											18,100,000
UNITED STATES
Segment Reporting Information [Line Items]
Revenues from unrelated entities									8,751,352,000	7,715,760,000	7,346,254,000
Total revenues									8,751,352,000	7,715,760,000	7,346,254,000
Operating income (loss)									545,818,000	480,781,000	463,201,000
Capital expenditures									43,859,000	42,297,000	31,903,000
Depreciation and amortization of property, plant and equipment									40,196,000	34,291,000	35,689,000
Contract assets	152,286,000				135,135,000				152,286,000	135,135,000	115,105,000
Contract liabilities	601,042,000				536,385,000				601,042,000	536,385,000	520,249,000
Long-lived assets	1,820,489,000				1,603,188,000				1,820,489,000	1,603,188,000	1,573,862,000
Total assets	4,197,584,000				3,493,784,000				4,197,584,000	3,493,784,000	3,251,695,000
UNITED STATES | United States electrical construction and facilities services segment
Segment Reporting Information [Line Items]
Revenues from unrelated entities									2,216,600,000	1,954,323,000	1,829,567,000
UNITED STATES | United States Mechanical Construction And Facilities Services
Segment Reporting Information [Line Items]
Revenues from unrelated entities									3,340,337,000	2,962,843,000	2,880,148,000
UNITED STATES | United States Building Services
Segment Reporting Information [Line Items]
Revenues from unrelated entities									2,106,872,000	1,875,485,000	1,753,703,000
UNITED STATES | United States Industrial Services
Segment Reporting Information [Line Items]
Revenues from unrelated entities									1,087,543,000	923,109,000	882,836,000
UNITED KINGDOM | United Kingdom Building Services
Segment Reporting Information [Line Items]
Revenues from unrelated entities									423,259,000	414,871,000	340,745,000
Operating Segments [Member] | UNITED STATES | United States electrical construction and facilities services segment
Segment Reporting Information [Line Items]
Revenues from unrelated entities									2,219,974,000	1,957,819,000
Total revenues									2,220,582,000	1,959,978,000	1,836,985,000
Operating income (loss)									161,684,000	139,430,000	150,001,000
Restructuring expenses									(445,000)	0
Capital expenditures									5,876,000	5,993,000	4,797,000
Depreciation and amortization of property, plant and equipment									7,550,000	6,221,000	6,545,000
Contract assets	50,813,000				38,412,000				50,813,000	38,412,000	35,060,000
Contract liabilities	173,967,000				163,951,000				173,967,000	163,951,000	178,454,000
Long-lived assets	215,780,000				201,333,000				215,780,000	201,333,000	180,990,000
Total assets	834,802,000				702,112,000				834,802,000	702,112,000	617,471,000
Operating Segments [Member] | UNITED STATES | United States Mechanical Construction And Facilities Services
Segment Reporting Information [Line Items]
Revenues from unrelated entities									3,351,918,000	2,975,751,000
Total revenues									3,370,960,000	2,998,918,000	2,911,033,000
Operating income (loss)									225,040,000	219,853,000	192,167,000
Capital expenditures									7,890,000	7,504,000	6,665,000
Depreciation and amortization of property, plant and equipment									8,764,000	7,803,000	7,504,000
Contract assets	61,225,000				49,302,000				61,225,000	49,302,000	50,302,000
Contract liabilities	317,083,000				280,846,000				317,083,000	280,846,000	288,699,000
Long-lived assets	530,561,000				334,628,000				530,561,000	334,628,000	340,030,000
Total assets	1,536,325,000				1,081,005,000				1,536,325,000	1,081,005,000	1,071,164,000
Operating Segments [Member] | UNITED STATES | United States Building Services
Segment Reporting Information [Line Items]
Total revenues									2,182,390,000	1,942,663,000	1,812,763,000
Operating income (loss)									114,754,000	93,827,000	81,720,000
Restructuring expenses									(1,078,000)	(882,000)
Capital expenditures									14,291,000	10,414,000	10,745,000
Depreciation and amortization of property, plant and equipment									12,728,000	10,324,000	11,051,000
Contract assets	30,428,000				33,304,000				30,428,000	33,304,000	26,028,000
Contract liabilities	97,588,000				79,281,000				97,588,000	79,281,000	48,481,000
Long-lived assets	458,915,000				436,887,000				458,915,000	436,887,000	409,718,000
Total assets	996,664,000				846,221,000				996,664,000	846,221,000	764,085,000
Operating Segments [Member] | UNITED STATES | United States Industrial Services
Segment Reporting Information [Line Items]
Total revenues									1,111,264,000	930,724,000	885,198,000
Operating income (loss)									44,340,000	27,671,000	39,313,000
Capital expenditures									15,802,000	18,386,000	9,696,000
Depreciation and amortization of property, plant and equipment									11,154,000	9,943,000	10,589,000
Contract assets	9,820,000				14,117,000				9,820,000	14,117,000	3,715,000
Contract liabilities	12,404,000				12,307,000				12,404,000	12,307,000	4,615,000
Long-lived assets	615,233,000				630,340,000				615,233,000	630,340,000	643,124,000
Total assets	829,793,000				864,446,000				829,793,000	864,446,000	798,975,000
Operating Segments [Member] | UNITED KINGDOM | United Kingdom Building Services
Segment Reporting Information [Line Items]
Total revenues									423,259,000	414,871,000	340,745,000
Operating income (loss)									18,323,000	15,930,000	12,905,000
Capital expenditures									3,598,000	870,000	2,166,000
Depreciation and amortization of property, plant and equipment									2,942,000	3,447,000	3,371,000
Contract assets	25,544,000				23,108,000				25,544,000	23,108,000	7,516,000
Contract liabilities	22,600,000				15,905,000				22,600,000	15,905,000	3,907,000
Long-lived assets	9,622,000				9,264,000				9,622,000	9,264,000	11,729,000
Total assets	181,147,000				146,379,000				181,147,000	146,379,000	131,806,000
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Operating income (loss)									(101,726,000)	(90,415,000)	(87,808,000)
Restructuring expenses									0	(1,424,000)
Capital expenditures									975,000	312,000	615,000
Depreciation and amortization of property, plant and equipment									807,000	734,000	855,000
Long-lived assets	1,431,000				1,072,000				1,431,000	1,072,000	1,494,000
Total assets	$ 451,627,000				$ 448,644,000				451,627,000	448,644,000	582,403,000
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenues									(133,844,000)	(116,523,000)	$ (99,725,000)
Intersegment Eliminations [Member] | UNITED STATES | United States electrical construction and facilities services segment
Segment Reporting Information [Line Items]
Revenues from unrelated entities									(3,374,000)	(3,496,000)
Intersegment Eliminations [Member] | UNITED STATES | United States Mechanical Construction And Facilities Services
Segment Reporting Information [Line Items]
Revenues from unrelated entities									$ (11,581,000)	$ (12,908,000)

Selected Unaudited Quarterly _3

Selected Unaudited Quarterly Information - Schedule of Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Selected Quarterly Financial Information [Abstract]
Revenues (in US dollars)	$ 2,403,940	$ 2,287,741	$ 2,324,202	$ 2,158,728	$ 2,229,308	$ 2,047,049	$ 1,953,886	$ 1,900,388	$ 9,174,611	$ 8,130,631	$ 7,686,999
Gross profit (in US dollars)	364,747	335,987	346,380	308,754	336,151	309,339	290,844	269,119	1,355,868	1,205,453	1,147,012
Impairment loss on goodwill and identifiable intangible assets					0	0	907	0	0	907	57,819
Net income attributable to EMCOR Group, Inc. (in US dollars)	$ 86,924	$ 81,834	$ 83,972	$ 72,410	$ 77,968	$ 79,373	$ 70,816	$ 55,374	$ 325,140	$ 283,531	$ 227,196
Basic earnings (loss) per common share:
Basic EPS from continuing operations (in US dollars per share)	$ 1.54	$ 1.46	$ 1.49	$ 1.29	$ 1.39	$ 1.37	$ 1.22	$ 0.95	$ 5.78	$ 4.92	$ 3.85
Basic EPS from discontinued operation (in US dollars per share)	0	0	0	0	(0.02)	(0.01)	0	0	0	(0.04)	(0.01)
Net income attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	1.54	1.46	1.49	1.29	1.37	1.36	1.22	0.95	5.78	4.88	3.84
Diluted earnings (loss) per common share:
Diluted EPS from continuing operations (in US dollars per share)	1.54	1.45	1.49	1.28	1.38	1.36	1.21	0.94	5.75	4.89	3.83
Diluted EPS from discontinued operation (in US dollars per share)	0	0	0	0	(0.02)	(0.01)	0	0	0	(0.04)	(0.01)
Net income attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	$ 1.54	$ 1.45	$ 1.49	$ 1.28	$ 1.36	$ 1.35	$ 1.21	$ 0.94	$ 5.75	$ 4.85	$ 3.82

Schedule II - Valuation and Q_2

Schedule II - Valuation and Qualifying Accounts (Details) - Allowance for Doubtful Accounts - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year		$ 15,361	$ 17,230	$ 12,252
Costs and Expenses		2,628	2,123	7,264
Deductions	[1]	(3,523)	(3,992)	(2,286)
Balance at End of Year		$ 14,466	$ 15,361	$ 17,230
[1]	Deductions primarily represent uncollectible balances of accounts receivable written off, net of recoveries.