Watsco (WSO) 10-K 28 Feb 19 2018 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Feb. 25, 2019	Jun. 29, 2018
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Entity Registrant Name	WATSCO INC
Entity Central Index Key	105,016
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 5,768
Trading Symbol	WSO
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity Small Business	false
Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		32,137,525
Common Class B [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		5,397,345

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Revenues	$ 4,546,653		$ 4,341,955		$ 4,220,702
Cost of sales	3,426,401		3,276,296		3,186,118
Gross profit	1,120,252		1,065,659		1,034,584
Selling, general and administrative expenses	757,452		715,671		688,952
Other income	9,282		3,886
Operating income	372,082		353,874		345,632
Interest expense, net	2,740		6,363		3,713
Income before income taxes	369,342		347,511		341,919
Income taxes	72,813		90,221		105,936
Net income	296,529		257,290		235,983
Less: net income attributable to non-controlling interest	53,597		49,069		53,173
Net income attributable to Watsco, Inc.	$ 242,932		$ 208,221		$ 182,810
Earnings per share for Common and Class B common stock:
Basic	$ 6.50	[1]	$ 5.81	[1]	$ 5.16
Diluted	$ 6.49	[1]	$ 5.81	[1]	$ 5.15
[1]	Quarterly and year-to-date earnings per share are calculated on an individual basis; therefore, the sum of earnings per share amounts for the quarters may not equal earnings per share amounts for the year.

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net income	$ 296,529	$ 257,290	$ 235,983
Other comprehensive (loss) income, net of tax
Foreign currency translation adjustment	(20,493)	15,993	6,211
Unrealized gain (loss) on cash flow hedging instruments	1,918	(702)	(965)
Reclassification of (gain) loss on cash flow hedging instruments into earnings	(157)	(358)	323
Unrealized (loss) gain on equity securities		(15)	14
Other comprehensive (loss) income	(18,732)	14,918	5,583
Comprehensive income	277,797	272,208	241,566
Less: comprehensive income attributable to non-controlling interest	46,913	54,678	55,382
Comprehensive income attributable to Watsco, Inc.	$ 230,884	$ 217,530	$ 186,184

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 82,894	$ 80,496
Accounts receivable, net	501,908	478,133
Inventories	837,129	761,314
Other current assets	19,875	17,454
Total current assets	1,441,806	1,337,397
Property and equipment, net	91,046	91,198
Goodwill	391,998	382,729
Intangible assets, net	147,851	161,065
Other assets	88,332	74,488
Total assets	2,161,033	2,046,877
Current liabilities:
Current portion of other long-term obligations	246	244
Accounts payable	200,229	230,476
Accrued expenses and other current liabilities	157,091	185,757
Total current liabilities	357,566	416,477
Long-term obligations:
Borrowings under revolving credit agreement	135,200	21,800
Other long-term obligations, net of current portion	552	285
Total long-term obligations	135,752	22,085
Deferred income taxes and other liabilities	66,002	57,338
Commitments and contingencies
Watsco, Inc. shareholders' equity:
Preferred stock, $0.50 par value, 10,000,000 shares authorized; no shares issued
Paid-in capital	832,121	804,008
Accumulated other comprehensive loss, net of tax	(45,968)	(34,221)
Retained earnings	627,969	594,556
Treasury stock, at cost, 4,823,988 shares of Common stock and 48,263 shares of Class B common stock at both December 31, 2018 and 2017, respectively	(87,440)	(87,440)
Total Watsco, Inc. shareholders' equity	1,347,849	1,297,953
Non-controlling interest	253,864	253,024
Total shareholders' equity	1,601,713	1,550,977
Total liabilities and shareholders' equity	2,161,033	2,046,877
Common Stock
Watsco, Inc. shareholders' equity:
Common stock, $0.50 par value	18,476	18,412
Class B Common Stock
Watsco, Inc. shareholders' equity:
Common stock, $0.50 par value	$ 2,691	$ 2,638

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Preferred stock, par value	$ 0.50	$ 0.50
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Common Stock
Common stock, par value	$ 0.50	$ 0.50
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares outstanding	36,952,762	36,825,128
Treasury stock, shares	4,823,988	4,823,988
Class B Common Stock
Common stock, par value	$ 0.50	$ 0.50
Common stock, shares authorized	10,000,000	10,000,000
Common stock, shares outstanding	5,381,132	5,275,838
Treasury stock, shares	48,263	48,263

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock, Class B Common Stock and Preferred Stock	Paid-In Capital	Accumulated Other Comprehensive Loss	Retained Earnings	Treasury Stock	Non-controlling Interest
Beginning balance at Dec. 31, 2015	$ 1,203,721	$ 20,841	$ 602,522	$ (46,904)	$ 495,276	$ (114,425)	$ 246,411
Beginning balance (in shares) at Dec. 31, 2015		35,311,493
Net income	235,983				182,810		53,173
Other comprehensive gain (loss)	5,583			3,374			2,209
Issuances of non-vested restricted shares of common stock (in shares)		183,144
Issuances of non-vested restricted shares of common stock		$ 92	(92)
Forfeitures of non-vested restricted shares of common stock (in shares)		(26,000)
Forfeitures of non-vested restricted shares of common stock		$ (13)	13
Common stock contribution to 401(k) plan	2,348	$ 10	2,338
Common stock contribution to 401(k) plan (in shares)		20,045
Stock issuances from exercise of stock options and employee stock purchase plan (in shares)		72,482
Stock issuances from exercise of stock options and employee stock purchase plan	5,696	$ 36	5,660
Retirement of common stock (in shares)		(30,761)
Retirement of common stock	(4,018)	$ (15)	(4,003)
Share-based compensation	11,848		11,848
Cash dividends declared and paid on Common and Class B common stock	(127,604)				(127,604)
Decrease in non-controlling interest in Carrier Enterprise II	(42,909)		(25,936)				(16,973)
Distributions to non-controlling interest	(38,900)						(38,900)
Ending balance at Dec. 31, 2016	1,251,748	$ 20,951	592,350	(43,530)	550,482	(114,425)	245,920
Ending balance (in shares) at Dec. 31, 2016		35,530,403
Net income	257,290				208,221		49,069
Other comprehensive gain (loss)	14,918			9,309			5,609
Issuances of non-vested restricted shares of common stock (in shares)		176,899
Issuances of non-vested restricted shares of common stock		$ 88	(88)
Forfeitures of non-vested restricted shares of common stock (in shares)		(10,000)
Forfeitures of non-vested restricted shares of common stock		$ (5)	5
Common stock contribution to 401(k) plan	2,428	$ 8	2,420
Common stock contribution to 401(k) plan (in shares)		16,389
Stock issuances from exercise of stock options and employee stock purchase plan (in shares)		49,166
Stock issuances from exercise of stock options and employee stock purchase plan	5,287	$ 24	5,263
Retirement of common stock (in shares)		(32,804)
Retirement of common stock	(4,717)	$ (16)	(4,701)
Share-based compensation	13,536		13,536
Net proceeds from the sale of Common stock	247,433		220,448			26,985
Net proceeds from the sale of Common stock (in shares)		1,498,662
Cash dividends declared and paid on Common and Class B common stock	(164,147)				(164,147)
Investment in unconsolidated entity	12,720						12,720
Decrease in non-controlling interest in Carrier Enterprise II	(42,688)		(25,225)				(17,463)
Distributions to non-controlling interest	(42,831)						(42,831)
Ending balance at Dec. 31, 2017	1,550,977	$ 21,050	804,008	(34,221)	594,556	(87,440)	253,024
Ending balance (in shares) at Dec. 31, 2017		37,228,715
Cumulative-effect adjustment at Dec. 31, 2017				301	(301)
Net income	296,529				242,932		53,597
Other comprehensive gain (loss)	(18,732)			(12,048)			(6,684)
Issuances of non-vested restricted shares of common stock (in shares)		142,865
Issuances of non-vested restricted shares of common stock		$ 71	(71)
Forfeitures of non-vested restricted shares of common stock (in shares)		(10,000)
Forfeitures of non-vested restricted shares of common stock		$ (5)	5
Common stock contribution to 401(k) plan	2,945	$ 9	2,936
Common stock contribution to 401(k) plan (in shares)		17,318
Stock issuances from exercise of stock options and employee stock purchase plan (in shares)		64,423
Stock issuances from exercise of stock options and employee stock purchase plan	7,852	$ 32	7,820
Retirement of common stock (in shares)		(28,781)
Retirement of common stock	(5,044)	$ (14)	(5,030)
Share-based compensation	15,631		15,631
Cash dividends declared and paid on Common and Class B common stock	(209,218)				(209,218)
Common stock issued for Alert Labs Inc. (in shares)		47,103
Common stock issued for Alert Labs Inc.	6,846	$ 24	6,822
Investment in unconsolidated entity	752						752
Distributions to non-controlling interest	(46,825)						(46,825)
Ending balance at Dec. 31, 2018	$ 1,601,713	$ 21,167	$ 832,121	$ (45,968)	$ 627,969	$ (87,440)	$ 253,864
Ending balance (in shares) at Dec. 31, 2018		37,461,643

Consolidated Statements of Sh_2

Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash dividends declared and paid, common stock	$ 5.60	$ 4.60	$ 3.60

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 296,529	$ 257,290	$ 235,983
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	22,095	22,033	20,066
Share-based compensation	15,508	13,293	12,319
Deferred income tax provision (benefit)	8,290	(10,735)	2,720
Non-cash contribution to 401(k) plan	2,945	2,428	2,348
Provision for doubtful accounts	2,619	1,991	3,487
Loss (gain) on sale of property and equipment	27	115	(189)
Other income from investment in unconsolidated entity	(9,282)	(3,886)
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	(28,831)	(1,676)	(26,941)
Inventories	(78,954)	(73,403)	(9,729)
Accounts payable and other liabilities	(57,398)	99,956	43,734
Other, net	(2,991)	(886)	(2,067)
Net cash provided by operating activities	170,557	306,520	281,731
Cash flows from investing activities:
Capital expenditures	(17,153)	(17,876)	(43,577)
Business acquisitions, net of cash acquired	(5,626)
Investment in unconsolidated entity	(3,760)	(63,600)
Proceeds from sale of property and equipment	228	168	744
Net cash used in investing activities	(26,311)	(81,308)	(42,833)
Cash flows from financing activities:
Dividends on Common and Class B common stock	(209,218)	(164,147)	(127,604)
Distributions to non-controlling interest	(46,825)	(42,831)	(38,900)
Repurchases of common stock to satisfy employee withholding tax obligations	(3,782)	(4,674)	(3,975)
Payment of fees related to revolving credit agreement	(790)
Net proceeds from the sale of Common stock		247,744
Purchase of additional ownership from non-controlling interest		(42,688)	(42,909)
Net proceeds (repayments) of other long-term obligations	269	(19)	(150)
Proceeds from non-controlling interest for investment in unconsolidated entity	752	12,720
Net proceeds from issuances of common stock	6,591	5,244	5,653
Net cash used in financing activities	(139,603)	(202,145)	(217,891)
Effect of foreign exchange rate changes on cash and cash equivalents	(2,245)	1,419	(226)
Net increase in cash and cash equivalents	2,398	24,486	20,781
Cash and cash equivalents at beginning of year	80,496	56,010	35,229
Cash and cash equivalents at end of year	82,894	80,496	56,010
Prior Revolving Credit Agreement [Member]
Cash flows from financing activities:
Net repayments under revolving credit agreement	(21,800)	$ (213,494)	$ (10,006)
Revolving Credit Agreement [Member]
Cash flows from financing activities:
Net repayments under revolving credit agreement	$ 135,200

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2018
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Organization, Consolidation and Presentation Watsco, Inc. (collectively with its subsidiaries, “Watsco,” “we,” “us,” or “our”) was incorporated in Florida in 1956 and is the largest distributor of air conditioning, heating and refrigeration equipment and related parts and supplies (“HVAC/R”) in the HVAC/R distribution industry in North America. At December 31, 2018, we operated from 571 locations in 37 U.S. states, Canada, Mexico, and Puerto Rico with additional market coverage on an export basis to portions of Latin America and the Caribbean. The consolidated financial statements include the accounts of Watsco, all of its wholly owned subsidiaries and the accounts of three joint ventures with Carrier Corporation (“Carrier”), in each of which Watsco maintains a controlling interest. All significant intercompany balances and transactions have been eliminated in consolidation. Foreign Currency Translation and Transactions The functional currency of our operations in Canada is the Canadian dollar. Foreign currency denominated assets and liabilities are translated into U.S. dollars at the exchange rates in effect at the balance sheet date, and income and expense items are translated at the average exchange rates in effect during the applicable period. The aggregate effect of foreign currency translation is recorded in accumulated other comprehensive loss in our consolidated balance sheets. Our net investment in our Canadian operations is recorded at the historical rate and the resulting foreign currency translation adjustments are included in accumulated other comprehensive loss in our consolidated balance sheets. Gains or losses resulting from transactions denominated in U.S. dollars are recognized in earnings primarily within cost of sales in our consolidated statements of income. Our operations in Mexico consider their functional currency to be the U.S. dollar because the majority of their transactions are denominated in U.S. dollars. Gains or losses resulting from transactions denominated in Mexican pesos are recognized in earnings primarily within selling, general and administrative expenses in our consolidated statements of income. Equity Method Investments Investments in which we have the ability to exercise significant influence, but do not control, are accounted for under the equity method of accounting and are included in other assets in our consolidated balance sheets. Under this method of accounting, our proportionate share of the net income or loss of the investee is included in other income in our consolidated statements of income. The excess, if any, of the carrying amount of our investment over our ownership percentage in the underlying net assets of the investee is attributed to certain fair value adjustments with the remaining portion recognized as goodwill. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses for the reporting period. Significant estimates include valuation reserves for accounts receivable, inventories and income taxes, reserves related to loss contingencies and the valuation of goodwill, indefinite lived intangible assets and long-lived assets. While we believe that these estimates are reasonable, actual results could differ from such estimates. Cash Equivalents All highly liquid instruments purchased with original maturities of three months or less are considered to be cash equivalents. Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable primarily consist of trade receivables due from customers and are stated at the invoiced amount less an allowance for doubtful accounts. An allowance for doubtful accounts is maintained for estimated losses resulting from the inability of customers to make required payments. When preparing these estimates, we consider a number of factors, including the aging of a customer’s account, past transactions with customers, creditworthiness of specific customers, historical trends and other information. Upon determination that an account is uncollectible, the receivable balance is written off. At December 31, 2018 and 2017, the allowance for doubtful accounts totaled $6,503 and $6,049, respectively. Inventories Inventories consist of air conditioning, heating and refrigeration equipment and related parts and supplies and are valued at the lower of cost using the weighted-average cost basis and the first-in, first-out methods, or net realizable value. As part of the valuation process, inventories are adjusted to reflect excess, slow-moving and damaged inventories at their estimated net realizable value. Inventory policies are reviewed periodically, reflecting current risks, trends and changes in industry conditions. A reserve for estimated inventory shrinkage is also maintained to consider inventory shortages determined from cycle counts and physical inventories. Vendor Rebates We have arrangements with several vendors that provide rebates payable to us when we achieve any of a number of measures, generally related to the volume level of purchases. We account for such rebates as a reduction of inventory until we sell the product, at which time such rebates are reflected as a reduction of cost of sales in our consolidated statements of income. Throughout the year, we estimate the amount of the rebate based on our estimate of purchases to date relative to the purchase levels that mark our progress toward earning the rebates. We continually revise our estimates of earned vendor rebates based on actual purchase levels. At December 31, 2018 and 2017, we had $11,603 and $11,621, respectively, of rebates recorded as a reduction of inventory. Substantially all vendor rebate receivables are collected within three months immediately following the end of the year. Equity Securities Investments in equity securities are recorded at fair value using the specific identification method and are included in other assets in our consolidated balance sheets. Unrealized holding gains and losses, net of deferred taxes, were included in accumulated other comprehensive loss within shareholders’ equity for 2017 and 2016. For 2018, changes in the fair value of equity securities were recognized through income rather than comprehensive income. Dividend and interest income are recognized in the statements of income when earned. Property and Equipment Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization of property and equipment is computed using the straight-line method. Buildings and improvements are depreciated or amortized over estimated useful lives ranging from 3-40 years. Leasehold improvements are amortized over the shorter of the respective lease terms or estimated useful lives. Furniture and fixtures are depreciated over estimated useful lives ranging from 5-7 years. Estimated useful lives for other depreciable assets range from 3-10 years. Goodwill and Intangible Assets Goodwill is recorded when the purchase price paid for an acquisition exceeds the fair value of the net identified tangible and intangible assets acquired. We evaluate goodwill for impairment annually or more frequently when an event occurs or circumstances change that indicate that the carrying value may not be recoverable. We test goodwill for impairment by first comparing the fair value of our reporting unit to its carrying value. If the fair value is determined to be less than the carrying value, a second step is performed to measure the amount of impairment loss. On January 1, 2019, we performed our annual evaluation of goodwill impairment and determined that the estimated fair value of our reporting unit significantly exceeded its carrying value. Intangible assets primarily consist of the value of trade names and trademarks, distributor agreements, customer relationships and . Indefinite lived intangibles not subject to amortization are assessed for impairment at least annually, or more frequently if events or changes in circumstances indicate they may be impaired, by comparing the fair value of the intangible asset to its carrying amount to determine if a write-down to fair value is required. Finite lived intangible assets are amortized using the straight-line method over their respective estimated useful lives. We perform our annual impairment tests each year and have determined there to be no impairment for any of the periods presented. There were no events or circumstances identified from the date of our assessment that would require an update to our annual impairment tests. Long-Lived Assets Long-lived assets, other than goodwill and intangible assets, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. Recoverability is evaluated by determining whether the amortization of the balance over its remaining life can be recovered through undiscounted future operating cash flows. We measure the impairment loss based on projected discounted cash flows using a discount rate reflecting the average cost of funds and compared to the asset’s carrying value. As of December 31, 2018 there were no such events or circumstances. Fair Value Measurements We carry various assets and liabilities at fair value in the consolidated balance sheets. Fair value is defined as the price that would be received for an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. Fair value measurements are classified based on the following fair value hierarchy: Level 1 Quoted prices in active markets for identical assets or liabilities. An active market for an asset or liability is a market in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2 Observable inputs other than Level 1 prices such as quoted prices in active markets for similar assets or liabilities; quoted prices in markets that are not active; or model-driven valuations or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 Unobservable inputs for the asset or liability. These inputs reflect our own assumptions about the assumptions a market participant would use in pricing the asset or liability. Revenue Recognition Revenue primarily consists of sales of air conditioning, heating and refrigeration equipment and related parts and supplies. We generate our revenue primarily from the sale of finished products to customers; therefore, the significant majority of our contracts are short-term in nature and have only a single performance obligation to deliver products; therefore, we satisfy our performance obligation under such contracts when we transfer control of the product to the customer. Some contracts contain a combination of product sales and services, the latter of which is distinct and accounted for as a separate performance obligation. We satisfy our performance obligations for services when we render the services within the agreed-upon service period. Total service revenue is not material and accounted for less than 1% of our consolidated revenues for 2018. Revenue is recognized when control transfers to our customers when picked up or via shipment of products or delivery of services. We measure revenue as the amount of consideration we expect to be entitled to receive in exchange for those goods or services, net of any variable considerations (e.g., rights to return product, sales incentives, others) and any taxes collected from customers and subsequently remitted to governmental authorities. Revenue for shipping and handling charges is recognized when products are delivered to the customer. Product Returns We estimate product returns based on historical experience and record them on a gross basis . Substantially all customer returns relate to products that are returned under manufacturers’ warranty obligations. Accrued sales returns of $11,275 at December 31, 2018 were included in accrued expenses and other current liabilities in our consolidated balance sheet. Sales Incentives We estimate sales incentives expected to be paid over the term of the program based on the most likely amounts. Sales incentives are accounted for as a reduction in the transaction price and are generally paid on an annual basis. Advertising Costs Advertising costs are expensed as incurred. Advertising expense for the years ended December 31, 2018, 2017 and 2016, were $16,520, $24,677 and $22,242, respectively. See Note 2. Shipping and Handling Shipping and handling costs associated with inbound freight are capitalized to inventories and relieved through cost of sales as inventories are sold. Shipping and handling costs associated with the delivery of products is included in selling, general and administrative expenses. Shipping and handling costs included in selling, general and administrative expenses for the years ended December 31, 2018, 2017 and 2016, were $51,741, $47,670 and $42,809, respectively. Share-Based Compensation The fair value of stock option and non-vested restricted stock awards are expensed net of estimated forfeitures on a straight-line basis over the vesting period of the awards. Share-based compensation expense is included in selling, general and administrative expenses in our consolidated statements of income. Tax benefits resulting from tax deductions in excess of share-based compensation expense are recognized in our provision for income taxes in our consolidated statements of income. Income Taxes We record U.S. federal, state and foreign income taxes currently payable, as well as deferred taxes due to temporary differences between reporting income and expenses for financial statement purposes versus tax purposes. Deferred tax assets and liabilities reflect the temporary differences between the financial statement and income tax basis of assets and liabilities. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of a change in tax rates is recognized as income or expense in the period that includes the enactment date. We and our eligible subsidiaries file a consolidated U.S. federal income tax return. As income tax returns are generally not filed until well after the closing process for the December 31 financial statements is complete, the amounts recorded at December 31 reflect estimates of what the final amounts will be when the actual income tax returns are filed for that calendar year. In addition, estimates are often required with respect to, among other things, the appropriate state income tax rates to use in the various states that we and our subsidiaries are required to file, the potential utilization of operating loss carryforwards and valuation allowances required, if any, for tax assets that may not be realizable in the future. We recognize the financial statement benefit of a tax position only after determining that the relevant tax authority would more likely than not sustain the position following an audit. For tax positions meeting the “more-likely-than-not” threshold, the amount recognized in the financial statements is the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement with the relevant tax authority. Earnings per Share We compute earnings per share using the two-class method. The two-class method of computing earnings per share is an earnings allocation formula that determines earnings per share for common stock and any participating securities according to dividends declared (whether paid or unpaid) and participation rights in undistributed earnings. Shares of our non-vested restricted stock are considered participating securities because these awards contain a non-forfeitable right to dividends irrespective of whether the awards ultimately vest. Under the two-class method, earnings per common share for our Common and Class B common stock is computed by dividing the sum of distributed earnings to common shareholders and undistributed earnings allocated to common shareholders by the weighted-average number of shares of Common and Class B common stock outstanding for the period. In applying the two-class method, undistributed earnings are allocated to Common stock, Class B common stock and participating securities based on the weighted-average shares outstanding during the period. Diluted earnings per share reflects the dilutive effect of potential common shares from stock options. The dilutive effect of outstanding stock options is computed using the treasury stock method, which assumes any proceeds that could be obtained upon the exercise of stock options, would be used to purchase common stock at the average market price for the period. The assumed proceeds include the purchase price the optionee pays, the windfall tax benefit that we receive upon assumed exercise and the unrecognized compensation expense at the end of each period. Derivative Instruments and Hedging Activity We have used derivative instruments, including forward and option contracts and swaps, to manage our exposure to fluctuations in foreign currency exchange rates and interest rates. The use of these derivative instruments modifies the exposure of these risks with the intent to reduce the risk or cost to us. We use derivative instruments as risk management tools and not for trading purposes. All derivatives, whether designated as hedging relationships or not, are recorded on the balance sheet at fair value. Cash flows from derivative instruments are classified in the consolidated statements of cash flows in the same category as the cash flows from the items subject to the designated hedge or undesignated (economic) hedge relationships. The hedging designation may be classified as one of the following: No Hedging Designation. The gain or loss on a derivative instrument not designated as an accounting hedging instrument is recognized in earnings within selling, general and administrative expenses. Cash Flow Hedge. A hedge of a forecasted transaction or of the variability of cash flows to be received or paid related to a recognized asset or liability is considered a cash flow hedge. The effective portion of the change in the fair value of a derivative that is designated as a cash flow hedge is recorded in other comprehensive income and reclassified to earnings as a component of cost of sales in the period for which the hedged transaction affects earnings. Ineffective portions of changes in the fair value of cash flow hedges are recognized in earnings. Fair Value Hedge. A hedge of a recognized asset or liability or an unrecognized firm commitment is considered a fair value hedge. Fair value hedges, both the effective and ineffective portions of the changes in the fair value of the derivative, along with the gain or loss on the hedged item that is attributable to the hedged risk, are recorded in earnings. See Note 16 for additional information pertaining to derivative instruments. Loss Contingencies Accruals are recorded for various contingencies including self-insurance, legal proceedings, environmental matters, and other claims that arise in the normal course of business. The estimation process contains uncertainty because accruals are based on judgment, the probability of losses and, where applicable, the consideration of opinions of external legal counsel and actuarially determined estimates. Additionally, we record receivables from third party insurers when recovery has been determined to be probable. Recently Adopted Accounting Standards Revenue Recognition In May 2014, the Financial Accounting Standards Board (the “FASB”) issued a standard on revenue recognition that provides a single, comprehensive revenue recognition model for all contracts with customers. The standard is principle-based and provides a five-step model to determine the measurement of revenue and timing of when it is recognized. In 2015 and 2016, the FASB issued several updates to this standard. The adoption of this standard and its related amendments (collectively, the “New Revenue Standard”) on January 1, 2018 did not result in the recognition of a cumulative adjustment to opening retained earnings under the modified retrospective approach, nor did it have a significant impact on our consolidated net income, balance sheet or cash flow. See Note 2. Financial Instruments In January 2016, the FASB issued guidance related to certain aspects of recognition, measurement, presentation and disclosure of financial instruments. Most prominent among the changes to the standard is the requirement that changes in the fair value of equity investments, with certain exceptions, be recognized through net income rather than other comprehensive income. This guidance must be applied using a modified retrospective approach through a cumulative-effect adjustment to retained earnings and became effective for interim and annual periods beginning after December 15, 2017. The adoption of this guidance did not have a material impact on our consolidated financial statements. A cumulative-effect adjustment captured the previously held unrealized losses of $301 related to our equity securities carried at fair value. See Note 4. Stock Compensation In May 2017, the FASB issued guidance to clarify when to account for a change to the terms or conditions of a share-based payment award as a modification. Under the new guidance, modification accounting is required only if the fair value, the vesting conditions or the classification of the award (as equity or liability) changes as a result of the change in terms or conditions. This guidance must be applied prospectively and became effective for interim and annual periods beginning after December 15, 2017. The adoption of this guidance did not have a material impact on our consolidated financial statements. Derivatives and Hedging In August 2017, the FASB issued guidance to simplify the accounting for hedging derivatives. This guidance is effective prospectively and is effective for interim and annual periods beginning after December 15, 2018 with early adoption permitted. We elected to adopt this guidance during the quarter ended June 30, 2018, which did not have a material impact on our consolidated financial statements. Recently Issued Accounting Standards Not Yet Adopted Leases In February 2016, the FASB issued guidance on accounting for leases, which requires lessees to recognize most leases on their balance sheets for the rights and obligations created by those leases. In July 2018, updated guidance was issued which provides an additional transition method of adoption that allows entities to initially apply the standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings. We adopted this standard and its related amendments (collectively, the “New Lease Standard”) on January 1, 2019, using this additional transition method, and we have elected the available practical expedients upon adoption. Although we continue to evaluate the impact of the New Lease Standard on our consolidated balance sheet, we do not expect that it will have a material impact on our consolidated statements of income. Following adoption of the New Lease Standard, we record a right-of-use (“ROU”) asset and lease liability, representing our obligation to make lease payments for operating leases greater than one year in duration, measured on a discounted basis. We expect that the ROU asset and lease liability recorded will be approximately 10% of our total assets. In preparation for the adoption, we are implementing business processes and controls over the financial reporting of leases, which will facilitate our reporting under the New Lease Standard in the first quarter of 2019. See Note 18, under the caption “Operating Leases,” for our minimum lease commitments at December 31, 2018. Intangibles—Goodwill and Other In January 2017, the FASB issued guidance to simplify the subsequent measurement of goodwill by eliminating Step 2 from the goodwill impairment test. Under this updated standard, an entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, but the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. An entity also should consider income tax effects from any tax-deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if any. This guidance is effective prospectively and is effective for interim and annual periods beginning after December 15, 2019 with early adoption permitted. We do not expect the adoption of this guidance to have a material impact on our consolidated financial statements. Disclosure Update and Simplification In August 2018, the Securities and Exchange Commission (“SEC”) issued the final rule under SEC Release No. 33-10532, “Disclosure Update and Simplification,” that amends certain of its disclosure requirements that have become redundant, duplicative, overlapping, outdated or superseded. The amendments include removing the requirement to disclose information on geographic regions from the Description of Business section of Form 10-K and replacing the requirement that a registrant disclose the high and low trading prices of entity’s ordinary shares with a requirement to disclose the ticker symbol of its shares. Additionally, the final rule extends to interim periods the annual disclosure requirement of presenting changes in each caption of stockholders’ equity and the amount of dividends per share. These disclosures are required to be provided for the current and comparative year-to-date interim periods. The final rule is effective for all filings on or after November 5, 2018. We have adopted all relevant disclosure requirements for our Annual Report on Form 10-K for the year ended December 31, 2018.

REVENUES

REVENUES	12 Months Ended
	Dec. 31, 2018
REVENUES	2. REVENUES We adopted the New Revenue Standard on January 1, 2018 using the modified retrospective approach. The New Revenue Standard did not have an impact on the amount or timing of our revenue recognition; however, certain payments to customers were reclassified from advertising expenses to a reduction from revenues, resulting in an immaterial impact to the individual financial statement line items of our consolidated statements of income. Results for reporting periods beginning on and after January 1, 2018 are presented under the New Revenue Standard, while prior period results have not been adjusted and continue to be reported under the accounting standards in effect for those periods. Disaggregation of Revenues The following table presents our revenues disaggregated by primary geographical regions and major product lines within our single reporting segment: Years Ended December 31, 2018 2017(1) 2016(1) Primary Geographical Regions: United States $ 4,126,639 $ 3,919,684 $ 3,813,204 Canada 291,685 269,603 267,220 Mexico 128,329 152,668 140,278 $ 4,546,653 $ 4,341,955 $ 4,220,702 Major Product Lines: HVAC equipment 67 % 67 % 66 % Other HVAC products 29 % 28 % 29 % Commercial refrigeration products 4 % 5 % 5 % 100 % 100 % 100 % (1) As noted above, prior period amounts have not been adjusted under the modified retrospective method and remain as originally reported for such periods. Practical Expedients We generally expense sales commissions when incurred because the amortization period is one year or less. These costs are recorded within selling, general and administrative expenses. We do not disclose the value of unsatisfied performance obligations for contracts with an original expected length of one year or less.

EARNINGS PER SHARE

EARNINGS PER SHARE	12 Months Ended
	Dec. 31, 2018
EARNINGS PER SHARE	3. EARNINGS PER SHARE The following table presents the calculation of basic and diluted earnings per share for our Common and Class B common stock: Years Ended December 31, 2018 2017 2016 Basic Earnings per Share: Net income attributable to Watsco, Inc. shareholders $ 242,932 $ 208,221 $ 182,810 Less: distributed and undistributed earnings allocated to non-vested restricted common stock 19,792 17,430 14,806 Earnings allocated to Watsco, Inc. shareholders $ 223,140 $ 190,791 $ 168,004 Weighted-average common shares outstanding - Basic 34,319,890 32,824,947 32,582,385 Basic earnings per share for Common and Class B common stock $ 6.50 $ 5.81 $ 5.16 Allocation of earnings for Basic: Common stock $ 206,355 $ 175,667 $ 154,021 Class B common stock 16,785 15,124 13,983 $ 223,140 $ 190,791 $ 168,004 Diluted Earnings per Share: Net income attributable to Watsco, Inc. shareholders $ 242,932 $ 208,221 $ 182,810 Less: distributed and undistributed earnings allocated to non-vested restricted common stock 19,788 17,427 14,801 Earnings allocated to Watsco, Inc. shareholders $ 223,144 $ 190,794 $ 168,009 Weighted-average common shares outstanding - Basic 34,319,890 32,824,947 32,582,385 Effect of dilutive stock options 54,379 37,686 34,119 Weighted-average common shares outstanding - Diluted 34,374,269 32,862,633 32,616,504 Diluted earnings per share for Common and Class B common stock $ 6.49 $ 5.81 $ 5.15 Diluted earnings per share for our Common stock assumes the conversion of all of our Class B common stock into Common stock as of the beginning of the fiscal year; therefore, no allocation of earnings to Class B common stock is required. At December 31, 2018, 2017 and 2016, our outstanding Class B common stock was convertible into 2,581,627, 2,601,996 and 2,711,811 shares of our Common stock, respectively. Diluted earnings per share excluded 74,270, 11,664 and 31,839 shares for the years ended December 31, 2018, 2017 and 2016, respectively, related to stock options with an exercise price per share greater than the average market value, resulting in an anti-dilutive effect on diluted earnings per share.

OTHER COMPREHENSIVE (LOSS) INCO

OTHER COMPREHENSIVE (LOSS) INCOME	12 Months Ended
	Dec. 31, 2018
OTHER COMPREHENSIVE INCOME (LOSS)	4. OTHER COMPREHENSIVE (LOSS) INCOME Other comprehensive (loss) income consists of the foreign currency translation adjustment associated with our Canadian operations’ use of the Canadian dollar as their functional currency and changes in the unrealized gains (losses) on cash flow hedging instruments and equity securities. The tax effects allocated to each component of other comprehensive (loss) income were as follows: Years Ended December 31, 2018 2017 2016 Foreign currency translation adjustment $ (20,493 ) $ 15,993 $ 6,211 Unrealized gain (loss) on cash flow hedging instruments 2,627 (961 ) (1,321 ) Income tax (expense) benefit (709 ) 259 356 Unrealized gain (loss) on cash flow hedging instruments, net of tax 1,918 (702 ) (965 ) Reclassification of (gain) loss on cash flow hedging instruments into earnings (215 ) (491 ) 442 Income tax expense (benefit) 58 133 (119 ) Reclassification of (gain) loss on cash flow hedging instruments into earnings, net of tax (157 ) (358 ) 323 Unrealized gain on equity securities — 51 27 Income tax expense — (66 ) (13 ) Unrealized (loss) gain on equity securities, net of tax — (15 ) 14 Other comprehensive (loss) income $ (18,732 ) $ 14,918 $ 5,583 The changes in each component of accumulated other comprehensive loss, net of tax, were as follows: Years Ended December 31, 2018 2017 2016 Foreign currency translation adjustment: Beginning balance $ (33,499 ) $ (43,459 ) $ (47,204 ) Current period other comprehensive (loss) income (13,105 ) 9,960 3,745 Ending balance (46,604 ) (33,499 ) (43,459 ) Cash flow hedging instruments: Beginning balance (421 ) 215 600 Current period other comprehensive income (loss) 1,151 (421 ) (579 ) Reclassification adjustment (94 ) (215 ) 194 Ending balance 636 (421 ) 215 Equity securities: Beginning balance (301 ) (286 ) (300 ) Cumulative-effect adjustment to retained earnings 301 — — Current period other comprehensive (loss) income — (15 ) 14 Ending balance — (301 ) (286 ) Accumulated other comprehensive loss, net of tax $ (45,968 ) $ (34,221 ) $ (43,530 )

SUPPLIER CONCENTRATION

SUPPLIER CONCENTRATION	12 Months Ended
	Dec. 31, 2018
SUPPLIER CONCENTRATION	5. SUPPLIER CONCENTRATION Purchases from our top ten suppliers comprised 84%, 84% and 85% of all purchases made in 2018, 2017 and 2016, respectively. Our largest supplier, Carrier and its affiliates, accounted for 62% of all purchases made in 2018, 2017 and 2016. See Note 19. A significant interruption by Carrier, or any of our other key suppliers, in the delivery of products could impair our ability to maintain current inventory levels and could materially impact our consolidated results of operations and consolidated financial position.

PROPERTY AND EQUIPMENT

PROPERTY AND EQUIPMENT	12 Months Ended
	Dec. 31, 2018
PROPERTY AND EQUIPMENT	6. PROPERTY AND EQUIPMENT Property and equipment, net, consists of: December 31, 2018 2017 Land $ 820 $ 820 Buildings and improvements 75,308 74,486 Machinery, vehicles and equipment 79,002 76,117 Furniture and fixtures 16,782 15,282 Computer hardware and software 50,853 47,377 222,765 214,082 Accumulated depreciation and amortization (131,719 ) (122,884 ) $ 91,046 $ 91,198 Depreciation and amortization expense related to property and equipment included in selling, general and administrative expenses for the years ended December 31, 2018, 2017 and 2016, were $16,747, $16,770 and $14,853, respectively.

DEBT

DEBT	12 Months Ended
	Dec. 31, 2018
DEBT	7. DEBT On December 5, 2018, we entered into an unsecured, five-year $500,000 syndicated multicurrency revolving credit agreement, which replaced in its entirety our prior five-year $300,000 revolving credit agreement, which was nearing maturity. Proceeds from the new facility were used to repay an aggregate of approximately $54,700 outstanding under the prior facility. Additional proceeds may be used for, among other things, funding seasonal working capital needs and other general corporate purposes, including acquisitions, dividends (if and as declared by our Board of Directors), capital expenditures, stock repurchases and issuances of letters of credit. The credit facility has a seasonal component from October 1 to March 31, during which the borrowing capacity may be reduced to $400,000 at our discretion (which would effectively reduce fees payable in respect of the unused portion of the commitment, as described below). Included in the credit facility are a $100,000 swingline subfacility, a $10,000 letter of credit subfacility, a $75,000 alternative currency borrowing sublimit and an $8,000 Mexican borrowing sublimit. The credit agreement matures on December 5, 2023. Borrowings under the credit facility bear interest at either LIBOR-based rates plus a spread, which ranges from 87.5 to 150.0 basis-points (LIBOR plus 87.5 basis-points at December 31, 2018), depending on our ratio of total debt to EBITDA, or on rates based on the highest of the Federal Funds Effective Rate plus 0.5%, the Prime Rate or the Eurocurrency Rate plus 1.0%, in each case plus a spread which ranges from 0 to 50.0 basis-points (0 basis-points at December 31, 2018), depending on our ratio of total debt to EBITDA. We pay a variable commitment fee on the unused portion of the commitment under the revolving credit agreement, ranging from 7.5 to 20.0 basis-points ( 7.5 At December 31, 2018, outstanding under the revolving credit agreement. The revolving credit agreement contains customary affirmative and negative covenants, including financial covenants with respect to consolidated leverage and interest coverage ratios, and other customary restrictions. We believe we were in compliance with all covenants at December 31, 2018.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2018
INCOME TAXES	8. INCOME TAXES On December 22, 2017, Public Law 115-97 “An Act to Provide for Reconciliation Pursuant to Titles II and V of the Concurrent Resolution on the Budget for Fiscal Year 2018” U.S. GAAP requires the impact of tax legislation to be recorded in the period of enactment. We recognized the tax effects of the TCJA for the year ended December 31, 2017 and recorded a provisional net income tax benefit of $9,955. This amount included an income tax benefit from the revaluation of U.S. deferred income taxes, partially offset by an estimate for income tax expense to record U.S. federal, state and foreign withholding tax on previously undistributed earnings of our foreign subsidiaries. We applied the guidance in Staff Accounting Bulletin 118 when accounting for the enactment-date effects of the TCJA. As of December 31, 2018, we have completed our accounting for all the enactment-date income tax effects of the TCJA. In 2018, we increased our previously estimated net income tax benefit by $ 1,819 11,774 U.S. federal and state income taxes on previously undistributed earnings of our foreign subsidiaries. The components of income tax expense from our wholly owned operations and investments and our controlling interest in joint ventures with Carrier are as follows: Years Ended December 31, 2018 2017 2016 U.S. Federal $ 54,345 $ 69,079 $ 86,719 State 11,631 10,643 9,801 Foreign 6,837 10,499 9,416 $ 72,813 $ 90,221 $ 105,936 Current $ 64,523 $ 100,956 $ 103,216 Deferred 8,290 (10,735 ) 2,720 $ 72,813 $ 90,221 $ 105,936 We calculate our income tax expense and our effective tax rate for 100% of income attributable to our wholly owned operations and for our controlling interest of income attributable to our joint ventures with Carrier, which are primarily taxed as partnerships for income tax purposes. Following is a reconciliation of the effective income tax rate: Years Ended December 31, 2018 2017 2016 U.S. federal statutory rate 21.0 % 35.0 % 35.0 % State income taxes, net of federal benefit and other 3.6 2.4 2.3 Excess tax benefits from share-based compensation (2.0 ) (2.7 ) (1.0 ) Tax effects on foreign income 0.5 (1.0 ) (0.1 ) GILTI 0.3 — — Tax credits and other — (0.6 ) (0.2 ) Repatriation transition tax (0.9 ) 3.0 — Deferred tax impact of enacted tax rate changes 0.3 (6.3 ) — Effective income tax rate attributable to Watsco, Inc. 22.8 29.8 36.0 Taxes attributable to non-controlling interest (3.1 ) (3.8 ) (5.0 ) Effective income tax rate 19.7 % 26.0 % 31.0 % The following is a summary of the significant components of our net deferred tax liabilities: December 31, 2018 2017 Deferred tax assets: Share-based compensation $ 21,517 $ 18,977 Capitalized inventory costs and inventory reserves 2,151 2,107 Allowance for doubtful accounts 1,057 929 Self-insurance reserves 206 153 Other 2,486 2,423 Net operating loss carryforwards 484 291 27,901 24,880 Valuation allowance — — Total deferred tax assets 27,901 24,880 Deferred tax liabilities: Deductible goodwill (69,600 ) (67,246 ) Depreciation (10,695 ) (5,519 ) Other (8,516 ) (5,189 ) Total deferred tax liabilities (88,811 ) (77,954 ) Net deferred tax liabilities (1) $ (60,910 ) $ (53,074 ) (1) Net deferred tax liabilities have been included in the consolidated balance sheets in deferred income taxes and other liabilities. Prior to enactment of the TCJA, U.S. income taxes had not been provided on undistributed earnings of our foreign subsidiaries as we had intended to reinvest such earnings permanently outside the U.S. or to repatriate such earnings only when it was tax effective to do so. The TCJA one-time repatriation transition tax and GILTI liabilities effectively taxed the undistributed earnings previously deferred from U.S. Federal income taxes. As of December 31 , 2018 we have accumulated undistributed earnings generated by our foreign subsidiaries of approximately Any additional taxes due with respect to such previously-taxed earnings, if repatriated, would generally be limited to foreign withholding. Deferred taxes have been recorded for foreign withholding taxes on certain earnings of our foreign consolidated subsidiaries expected to be repatriated. We do not intend to distribute the remaining previously-taxed foreign earnings and therefore have not recorded deferred taxes for foreign withholding on such earnings. The amount of foreign withholding that might be payable on the remaining amounts at December 31, 2018 is not material. Valuation allowances are provided to reduce the related deferred income tax assets to an amount which will, more likely than not, be realized. As a result of our assessment of the realization of deferred income tax assets, we have concluded that it is more likely than not that all of our deferred income tax assets will be realized and thus no valuation allowance was necessary at both December 31, 2018 and 2017. At December 31, 2018, there were state net operating loss carryforwards of $8,263, which expire in varying amounts from 2019 through 2038. These amounts are available to offset future taxable income. There were no federal net operating loss carryforwards at December 31, 2018. We are subject to United States federal income tax, income tax of multiple state jurisdictions and foreign income tax. We are subject to tax audits in the various jurisdictions until the respective statutes of limitations expire. We are no longer subject to United States federal tax examinations for tax years prior to 2015. For the majority of states and foreign jurisdictions, we are no longer subject to tax examinations for tax years prior to 2014. As of December 31, 2018 and 2017, the total amount of gross unrecognized tax benefits (excluding the federal benefit received from state positions) was $4,902 and $4,225, respectively. Of these totals, $3,997 and $3,457, respectively, (net of the federal benefit received from state positions) represent the amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate. Our continuing practice is to recognize penalties within selling, general and administrative expenses and interest related to income tax matters in income tax expense in the consolidated statements of income. As of December 31, 2018 and 2017, the cumulative amount of estimated accrued interest and penalties resulting from such unrecognized tax benefits was $755 and $540, respectively, and is included in deferred income taxes and other current liabilities in the accompanying consolidated balance sheets. The changes in gross unrecognized tax benefits are as follows: Balance at December 31, 2015 $ 3,513 Additions based on tax positions related to the current year 547 Reductions due to lapse of applicable statute of limitations and tax assessments (365 ) Balance at December 31, 2016 3,695 Additions based on tax positions related to the current year 801 Reductions due to lapse of applicable statute of limitations (271 ) Balance at December 31, 2017 4,225 Additions based on tax positions related to the current year 960 Reductions due to lapse of applicable statute of limitations (283 ) Balance at December 31, 2018 $ 4,902

SHARE-BASED COMPENSATION AND BE

SHARE-BASED COMPENSATION AND BENEFIT PLANS	12 Months Ended
	Dec. 31, 2018
SHARE-BASED COMPENSATION AND BENEFIT PLANS	9. SHARE-BASED COMPENSATION AND BENEFIT PLANS Share-Based Compensation Plans We maintain the 2014 Incentive Compensation Plan (the “2014 Plan”) that provides for the award of a broad variety of share-based compensation alternatives such as non-vested restricted stock, non-qualified stock options, incentive stock options, performance awards, dividend equivalents, deferred stock and stock appreciation rights at no less than 100% of the market price on the date the award is granted. To date, awards under the 2014 Plan consist of non-qualified stock options and non-vested restricted stock. The 2014 Plan replaced the Watsco, Inc. Amended and Restated 2001 Incentive Compensation Plan (the “2001 Plan”) upon its expiration in 2014. Under the 2014 Plan, the number of shares of Common and Class B common stock available for issuance is (i) 2,000,000, plus (ii) 45,421 shares of Common stock or Class B common stock that remained available for grant in connection with awards under the 2001 Plan as of the date our shareholders approved the 2014 Plan plus (iii) shares underlying currently outstanding awards issued under the 2001 Plan, which shares become reissuable under the 2014 Plan to the extent that such underlying shares are not issued due to their forfeiture, expiration, termination or otherwise. A total of 601,252 shares of Common stock, net of cancellations, and 626,387 shares of Class B common stock, had been awarded under the 2014 Plan as of December 31, 2018. As of December 31, 2018, 817,782 shares of common stock were reserved for future grants under the 2014 Plan. Options under the 2014 Plan vest over two to four years of service and have contractual terms of five years. Awards of non-vested restricted stock, which are granted at no cost to the employee, vest upon attainment of a specified age, generally toward the end of an employee’s career at age 62 or older. Vesting may be accelerated in certain circumstances prior to the original vesting date. The 2001 Plan expired during 2014; therefore, no additional options may be granted. There were 1,000 options to exercise common stock outstanding under the 2001 Plan at December 31, 2018. Options under the 2001 Plan vest over two to four years of service and have contractual terms of five years. The following is a summary of stock option activity under the 2014 Plan and the 2001 Plan as of and for the year ended December 31, 2018: Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Options outstanding at December 31, 2017 398,833 $ 136.44 Granted 188,550 173.48 Exercised (54,934 ) 114.09 Forfeited (26,832 ) 155.83 Expired (1,000 ) 122.62 Options outstanding at December 31, 2018 504,617 $ 151.71 3.31 $ 1,733 Options exercisable at December 31, 2018 71,487 $ 135.89 2.13 $ 826 The following is a summary of non-vested restricted stock activity as of and for the year ended December 31, 2018: Shares Weighted- Average Grant Date Fair Value Non-vested restricted stock outstanding at December 31, 2017 2,985,239 $ 51.22 Granted 142,865 167.06 Vested (55,502 ) 66.52 Forfeited (10,000 ) 142.52 Non-vested restricted stock outstanding at December 31, 2018 3,062,602 $ 48.72 The weighted-average grant date fair value of non-vested restricted stock granted during 2018, 2017 and 2016 was $167.06, $149.47 and $130.01, respectively. The fair value of non-vested restricted stock that vested during 2018, 2017 and 2016 was $9,637, $11,580 and $10,096, respectively. During 2018, 21,754 common stock with an aggregate fair market value of $3,775 were withheld as payment in lieu of cash to satisfy tax withholding obligations in connection with the vesting of restricted stock. During 2017, 32,454 shares of Common stock with an aggregate fair market value of $4,664 were withheld as payment in lieu of cash to satisfy tax withholding obligations in connection with the vesting of restricted stock. During 2016, 30,413 shares of Common and Class B common stock with an aggregate fair market value of $3,967 were withheld as payment in lieu of cash to satisfy tax withholding obligations in connection with the vesting of restricted stock. These shares were retired upon delivery. Share-Based Compensation Fair Value Assumptions The fair value of each stock option award is estimated on the date of grant using the Black-Scholes option pricing valuation model based on the weighted-average assumptions noted in the table below. The fair value of each stock option award, which is subject to graded vesting, is expensed, net of estimated forfeitures, on a straight-line basis over the requisite service period for each separately vesting portion of the stock option. We use historical data to estimate stock option forfeitures. The expected term of stock option awards granted represents the period of time that stock option awards granted are expected to be outstanding and was calculated using the simplified method for plain vanilla options, which we believe provides a reasonable estimate of expected life based on our historical data. The risk-free rate for periods within the contractual life of the stock option award is based on the yield curve of a zero-coupon United States Treasury bond on the date the stock option award is granted with a maturity equal to the expected term of the stock option award. Expected volatility is based on historical volatility of our stock. The following table presents the weighted-average assumptions used for stock options granted: Years Ended December 31, 2018 2017 2016 Expected term in years 4.25 4.25 4.25 Risk-free interest rate 2.69 % 1.77 % 1.24 % Expected volatility 17.11 % 17.41 % 18.65 % Expected dividend yield 3.13 % 2.82 % 2.54 % Grant date fair value $ 20.05 $ 17.23 $ 16.37 Exercise of Stock Options The total intrinsic value of stock options exercised during 2018, 2017 and 2016 was $3,500, $2,296 and $4,123, respectively. Cash received from the exercise of stock options during 2018, 2017 and 2016 was $5,006, $3,855 and $4,447, respectively. During 2018, 2017 and 2016, 7,027 shares of Common stock with an aggregate fair market value of $1,269, 350 shares of Common stock with an aggregate fair market value of $53 and 348 shares of Common stock with an aggregate fair market value of $51, respectively, were withheld as payment in lieu of cash for stock option exercises and related tax withholdings. These shares were retired upon delivery. Share-Based Compensation Expense The following table provides information on share-based compensation expense: Years Ended December 31, 2018 2017 2016 Stock options $ 2,014 $ 1,451 $ 1,149 Non-vested restricted stock 13,494 11,842 11,170 Share-based compensation expense $ 15,508 $ 13,293 $ 12,319 At December 31, 2018, there was $3,598 of unrecognized pre-tax compensation expense related to stock options granted under the 2014 Plan, which is expected to be recognized over a weighted-average period of approximately 1.8 years. The total fair value of stock options that vested during 2018, 2017 and 2016 was $1,607, $754 and $736, respectively. At December 31, 2018, there was $118,124 of unrecognized pre-tax compensation expense related to non-vested restricted stock, which is expected to be recognized over a weighted-average period of approximately 11.2 years. Of this amount, approximately $56,000 is related to awards granted to our Chief Executive Officer (“CEO”), of which approximately $9,000, $42,000 and $5,000 vest in approximately 4, 8 and 10 years upon his attainment of age 82, 86 and 88, respectively, and approximately $13,000 is related to awards granted to our President, of which approximately $12,000 and $1,000 vest in approximately 25 and 27 years upon his attainment of age 62 and 64, respectively . In the event that vesting is accelerated for any circumstance, as defined in the related agreements, the remaining unrecognized share-based compensation expense would be immediately recognized as a charge to earnings with a corresponding tax benefit. At December 31, 2018, we were obligated to issue 45,752 shares of non-vested restricted stock to our CEO that vest in 10 years and 23,297 shares of non-vested restricted stock to our President that vest in 25 years in connection with performance based incentive compensation. Employee Stock Purchase Plan The Watsco, Inc. Fourth Amended and Restated 1996 Qualified Employee Stock Purchase Plan (the “ESPP”) provides for up to 1,500,000 shares of Common stock to be available for purchase by our full-time employees with at least 90 days of service. The ESPP allows participating employees to purchase shares of Common stock at a 5% discount to the fair market value at specified times. During 2018, 2017 and 2016, employees purchased 5,151, 5,571 and 5,956 shares of Common stock at an average price of $168.21, $144.58 and $125.84 per share, respectively. Cash dividends received by the ESPP were reinvested in Common stock and resulted in the issuance of 4,338, 3,844 and 3,442 additional shares during 2018, 2017 and 2016, respectively. We received net proceeds of $1,585, $1,389 and $1,206, respectively, during 2018, 2017 and 2016, for shares of our Common stock purchased under the ESPP. At December 31, 2018, 477,256 shares remained available for purchase under the ESPP. 401(k) Plan We have a profit sharing retirement plan for our employees that is qualified under Section 401(k) of the Internal Revenue Code. Annual matching contributions are made based on a percentage of eligible employee compensation deferrals. The contribution has historically been made with the issuance of Common stock to the plan on behalf of our employees. For the years ended December 31, 2018, 2017 and 2016, we issued 17,318, 16,389 and 20,045 shares of Common stock, respectively, to the plan, representing the Common stock discretionary matching contribution of $2,945, $2,428 and $2,348, respectively.

PURCHASE OF ADDITIONAL OWNERSHI

PURCHASE OF ADDITIONAL OWNERSHIP INTEREST IN JOINT VENTURE	12 Months Ended
	Dec. 31, 2018
PURCHASE OF ADDITIONAL OWNERSHIP INTEREST IN JOINT VENTURE	10. PURCHASE OF ADDITIONAL OWNERSHIP INTEREST IN JOINT VENTURE In 2011, we formed a joint venture with Carrier, Carrier Enterprise Northeast LLC, which we refer to as Carrier Enterprise II. We initially owned a 60% controlling interest in Carrier Enterprise II. On November 29, 2016, we purchased an additional 10% ownership interest for cash consideration of $42,909, and, on February 13, 2017, we purchased an additional 10% ownership interest for cash consideration of $42,688, which together increased our controlling interest in Carrier Enterprise II to 80%.

INVESTMENT IN UNCONSOLIDATED EN

INVESTMENT IN UNCONSOLIDATED ENTITY	12 Months Ended
	Dec. 31, 2018
INVESTMENT IN UNCONSOLIDATED ENTITY	11. INVESTMENT IN UNCONSOLIDATED ENTITY On June 21, 2017, our first joint venture with Carrier, Carrier Enterprise, LLC, which we refer to as Carrier Enterprise I, acquired a 34.9% ownership interest in Russell Sigler, Inc. (“RSI”), an HVAC distributor with 2018 sales of approximately $770,000, operating from 30 locations in the Western U.S. We have an 80% controlling interest in Carrier Enterprise I, and Carrier has a 20% non-controlling interest. Carrier Enterprise I acquired its ownership interest in RSI for cash consideration of $63,600, of which we contributed $50,880, and Carrier contributed $12,720. Effective June 29, 2018, Carrier Enterprise I acquired an additional 1.4% ownership interest in RSI, which increased Carrier Enterprise I’s ownership interest in RSI to 36.3% for cash consideration of $3,760, of which we contributed $3,008 and Carrier contributed $752. Carrier Enterprise I is a party to a shareholders agreement (the “Shareholders Agreement”) with RSI and its shareholders. Pursuant to the Shareholders Agreement, RSI’s shareholders have the right to sell, and Carrier Enterprise I has the obligation to purchase, their respective shares of RSI for a purchase price determined based on either book value or a multiple of EBIT, the latter of which Carrier Enterprise I used to calculate the price paid for its investment in RSI. RSI’s shareholders may transfer their respective shares of RSI common stock only to members of the Sigler family or to Carrier Enterprise I, and, at any time from and after the date on which Carrier Enterprise I owns 85% or more of RSI’s outstanding common stock, it has the right, but not the obligation, to purchase from RSI’s shareholders the remaining outstanding shares of RSI common stock. Additionally, Carrier Enterprise I has the right to appoint two of RSI’s six board members. Given Carrier Enterprise I’s 36.3% ownership interest in RSI and its right to appoint two out of RSI’s six board members, this investment in RSI is accounted for under the equity method.

ACQUISITION

ACQUISITION	12 Months Ended
	Dec. 31, 2018
ACQUISITION	12. ACQUISITIONS On August 23, 2018, one of our wholly owned subsidiaries acquired Alert Labs Inc., a technology company based in Ontario, Canada for cash consideration of $ 5,889 On November 30, 2018, one of our wholly owned subsidiaries acquired certain assets and assumed certain liabilities of a wholesale distributor of air conditioning and heating products operating from three locations in North Carolina. The results of operations of these acquisitions have been included in the consolidated financial statements from their respective dates of acquisition. The pro forma effect of the acquisitions were not deemed significant to the consolidated financial statements.

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2018
GOODWILL AND INTANGIBLE ASSETS	13. GOODWILL AND INTANGIBLE ASSETS The changes in the carrying amount of goodwill are as follows: Balance at December 31, 2016 $ 379,737 Foreign currency translation adjustment 2,992 Balance at December 31, 2017 382,729 Acquired goodwill 13,301 Foreign currency translation adjustment (4,032 ) Balance at December 31, 2018 $ 391,998 Intangible assets are comprised of the following: December 31, Estimated Useful Lives 2018 2017 Indefinite lived intangible assets - Trade names, trademarks and distribution rights $ 119,188 $ 125,194 Finite lived intangible assets: Customer relationships 10-15 years 69,593 73,053 Patented and unpatented technology 7 1,600 — Trade name 10 years 1,150 1,150 Accumulated amortization (43,680 ) (38,332 ) Finite lived intangible assets, net 28,663 35,871 $ 147,851 $ 161,065 Amortization expense related to finite lived intangible assets included in selling, general and administrative expenses for the years ended December 31, 2018, 2017 and 2016, were $5,348, $5,263 and $5,213, respectively. Annual amortization of finite lived intangible assets for the next five years is expected to approximate the following: 2019 $ 5,000 2020 $ 5,000 2021 $ 4,200 2022 $ 3,400 2023 $ 2,800

SHAREHOLDERS' EQUITY

SHAREHOLDERS' EQUITY	12 Months Ended
	Dec. 31, 2018
SHAREHOLDERS' EQUITY	14. SHAREHOLDERS’ EQUITY Common Stock Common stock and Class B common stock share equally in earnings and are identical in most other respects except (i) Common stock is entitled to one vote on most matters and each share of Class B common stock is entitled to ten votes; (ii) shareholders of Common stock are entitled to elect 25% of the Board of Directors (rounded up to the nearest whole number) and Class B shareholders are entitled to elect the balance of the Board of Directors; (iii) cash dividends may be paid on Common stock without paying a cash dividend on Class B common stock and no cash dividend may be paid on Class B common stock unless at least an equal cash dividend is paid on Common stock and (iv) Class B common stock is convertible at any time into Common stock on a one-for-one basis at the option of the shareholder. Preferred Stock We are authorized to issue preferred stock with such designation, rights and preferences as may be determined from time to time by our Board of Directors. Accordingly, the Board of Directors is empowered, without shareholder approval, to issue preferred stock with dividend, liquidation, conversion, voting or other rights which could adversely affect the voting power or other rights of the holders of our Common stock and Class B common stock and, in certain instances, could adversely affect the market price of this stock. We had no preferred stock outstanding at December 31, 2018 or 2017. At-the-Market Offering Program On August 23, 2017, we entered into a sales agreement with Robert W. Baird & Co. Inc., which enabled the Company to issue and sell shares of Common stock in one or more negotiated transactions that are deemed to be “at the market” offerings as defined in Rule 415 under the Securities Act of 1933, as amended (the “Securities Act”), for a maximum aggregate offering amount of up to $250,000 (the “ATM Program”). The offer and sale of our Common stock pursuant to the ATM Program was registered under the Securities Act pursuant to our automatically effective shelf registration statement on Form S-3 (File No. 333-207831). During 2017, we sold 1,498,662 shares of Common stock under the ATM Program for net proceeds of $247,744. Direct costs of $311 incurred in connection with the offering were charged against the proceeds from the sale of Common stock and reflected as a reduction of paid-in capital. As of December 31, 2017, we had completed the offering of shares under the ATM Program. The net proceeds were primarily used to repay outstanding debt and for general corporate purposes. Stock Repurchase Plan In September 1999, our Board of Directors authorized the repurchase, at management’s discretion, of up to 7,500,000 shares of common stock in the open market or via private transactions. Shares repurchased under the program are accounted for using the cost method and result in a reduction of shareholders’ equity. No shares were repurchased during 2018, 2017 or 2016. In aggregate, 6,322,650 shares of Common stock and 48,263 shares of Class B common stock have been repurchased at a cost of $114,425 since the inception of the program. At December 31, 2018, there were 1,129,087 shares remaining authorized for repurchase under the program.

FINANCIAL INSTRUMENTS

FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2018
FINANCIAL INSTRUMENTS	15. FINANCIAL INSTRUMENTS Recorded Financial Instruments Recorded financial instruments consist of cash and cash equivalents, accounts receivable, accounts payable, the current portion of long-term obligations, borrowings under our revolving credit agreement and debt instruments included in other long-term obligations. At December 31, 2018 and 2017, the fair values of cash and cash equivalents, accounts receivable, accounts payable and the current portion of long-term obligations approximated their carrying values due to the short-term nature of these instruments. The fair values of variable rate borrowings under our revolving credit agreement and debt instruments included in long-term obligations also approximate their carrying value based upon interest rates available for similar instruments with consistent terms and remaining maturities. Off-Balance Sheet Financial Instruments At December 31, 2018 and 2017, we were contingently liable under standby letters of credit aggregating $ 1,222 2,430 which are primarily used as collateral to cover any contingency related to additional risk assessments pertaining to our self-insurance programs. Additionally, at December 31, 2018 and 2017, we were contingently liable under various performance bonds aggregating approximately $3,600 and $4,000, respectively, which are used as collateral to cover any contingencies related to our nonperformance under agreements with certain customers. We do not expect that any material losses or obligations will result from the issuance of the standby letters of credit or performance bonds because we expect to meet our obligations under our self-insurance programs and to certain customers in the ordinary course of business. Accordingly, the estimated fair value of these instruments is zero. Concentrations of Credit Risk Financial instruments which potentially subject us to concentrations of credit risk consist principally of accounts receivable. Concentrations of credit risk are limited due to the large number of customers comprising the customer base and their dispersion across many different geographical regions. We also have access to credit insurance programs which are used as an additional means to mitigate credit risk.

DERIVATIVES

DERIVATIVES	12 Months Ended
	Dec. 31, 2018
DERIVATIVES	16. DERIVATIVES We enter into foreign currency forward and option contracts to offset the earnings impact that foreign exchange rate fluctuations would otherwise have on certain monetary liabilities that are denominated in nonfunctional currencies. Cash Flow Hedging Instruments We enter into foreign currency forward contracts that are designated as cash flow hedges. The settlement of these derivatives results in reclassifications from accumulated other comprehensive loss to earnings for the period in which the settlement of these instruments occurs. The maximum period for which we hedge our cash flow using these instruments is 12 months. Accordingly, at December 31, 2018, all of our open foreign currency forward contracts had maturities of one year or less. The total notional value of our foreign currency exchange contracts designated as cash flow hedges at December 31, 2018 was $40,000, and such contracts have varying terms expiring through September 2019. The impact from foreign exchange derivative instruments designated as cash flow hedges was as follows: Years Ended December 31, 2018 2017 Gain (loss) recorded in accumulated other comprehensive loss $ 2,627 $ (961 ) (Gain) l oss reclassified from accumulated other comprehensive loss into earnings $ (215 ) $ (491 ) At December 31, 2018, we expected an estimated $1,450 pre-tax gain to be reclassified into earnings to reflect the fixed prices obtained from foreign exchange hedging within the next 12 months. Derivatives Not Designated as Hedging Instruments We have also entered into foreign currency forward and option contracts that are either not designated as hedges or did not qualify for hedge accounting. These derivative instruments were effective economic hedges for all of the periods presented. The fair value gains and losses on these contracts are recognized in earnings as a component of selling, general and administrative expenses. The total notional value of our foreign currency exchange contracts not designated as hedging instruments at December 31, 2018 was $6,800, and such contracts have varying terms expiring through We recognized gains (losses) of $129, $(829) and $(306) from foreign currency forward and option contracts not designated as hedging instruments in our consolidated statements of income for 2018, 2017 and 2016, respectively. The following table summarizes the fair value of derivative instruments, which consist solely of foreign exchange contracts, included in other current assets and accrued expenses and other current liabilities in our consolidated balance sheets. See Note 17. Asset Derivatives Liability Derivatives December 31, 2018 2017 2018 2017 Derivatives designated as hedging instruments $ 1,262 $ 70 $ 3 $ 773 Derivatives not designated as hedging instruments 58 180 11 184 Total derivative instruments $ 1,320 $ 250 $ 14 $ 957

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 31, 2018
FAIR VALUE MEASUREMENTS	17. FAIR VALUE MEASUREMENTS The following tables present our assets and liabilities carried at fair value that are measured on a recurring basis: Fair Value Measurements at December 31, 2018 Using Balance Sheet Location Total Level 1 Level 2 Level 3 Assets: Derivative financial instruments Other current assets $ 1,320 — $ 1,320 — Equity securities Other assets $ 279 $ 279 — — Liabilities: Derivative financial instruments Accrued expenses and other current liabilities $ 14 — $ 14 — Fair Value Measurements at December 31, 2017 Using Balance Sheet Location Total Level 1 Level 2 Level 3 Assets: Derivative financial instruments Other current assets $ 250 — $ 250 — Equity securities Other assets $ 332 $ 332 — — Liabilities: Derivative financial instruments Accrued expenses and other current liabilities $ 957 — $ 957 — The following is a description of the valuation techniques used for these assets and liabilities, as well as the level of input used to measure fair value: Equity securities – these investments are exchange-traded equity securities. Fair values for these investments are based on closing stock prices from active markets and are therefore classified within Level 1 of the fair value hierarchy. Derivative financial instruments – these derivatives are foreign currency forward and option contracts. See Note 16. Fair value is based on observable market inputs, such as forward rates in active markets; therefore, we classify these derivatives within Level 2 of the valuation hierarchy. There were no transfers in or out of Level 1 and Level 2 during 2018 or 2017.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2018
COMMITMENTS AND CONTINGENCIES	18. COMMITMENTS AND CONTINGENCIES Litigation, Claims and Assessments We are involved in litigation incidental to the operation of our business. We vigorously defend all matters in which we or our subsidiaries are named defendants and, for insurable losses, maintain significant levels of insurance to protect against adverse judgments, claims or assessments that may affect us. Although the adequacy of existing insurance coverage and the outcome of any legal proceedings cannot be predicted with certainty, based on the current information available, we do not believe the ultimate liability associated with any known claims or litigation will have a material adverse effect on our financial condition or results of operations. Self-Insurance Self-insurance reserves are maintained relative to company-wide casualty insurance and health benefit programs. The level of exposure from catastrophic events is limited by the purchase of stop-loss and aggregate liability reinsurance coverage. When estimating the self-insurance liabilities and related reserves, management considers a number of factors, which include historical claims experience, demographic factors, severity factors and valuations provided by independent third-party actuaries. Management reviews its assumptions with its independent third-party actuaries to evaluate whether the self-insurance reserves are adequate. If actual claims or adverse development of loss reserves occur and exceed these estimates, additional reserves may be required and could materially impact the consolidated results of operations. The estimation process contains uncertainty since management must use judgment to estimate the ultimate cost that will be incurred to settle reported claims and unreported claims for incidents incurred but not reported as of the balance sheet date. Reserves in the amounts of $ 2, 311 and $ 2,344 Variable Interest Entity As of December 31, 2018, in conjunction with our casualty insurance programs, limited equity interests are held in a captive insurance entity. The programs permit us to self-insure a portion of losses, to gain access to a wide array of safety-related services, to pool insurance risks and resources in order to obtain more competitive pricing for administration and reinsurance and to limit risk of loss in any particular year. The entity meets the definition of Variable Interest Entity (“VIE”); however, we do not meet the requirements to include this entity in the consolidated financial statements. The maximum exposure to loss related to our involvement with this entity is limited to approximately $3,900. See “Self-Insurance” above for further information on commitments associated with the insurance programs and Note 15, under the caption “Off-Balance Sheet Financial Instruments,” for further information on standby letters of credit. At December 31, 2018, there were no other entities that met the definition of a VIE. Operating Leases We are obligated under various non-cancelable operating lease agreements for real property, vehicles and equipment used in our operations with varying terms through 2028. At December 31, 2018, future minimum payments under non-cancelable operating leases over each of the next five years and thereafter were as follows: 2019 $ 70,388 2020 55,102 2021 41,321 2022 28,482 2023 15,712 Thereafter 8,245 Total minimum payments $ 219,250 Rental expense for the years ended December 31, 2018, 2017 and 2016, was $84,537, $84,076 and $83,260, respectively. Purchase Obligations At December 31, 2018, we were obligated under various non-cancelable purchase orders with our key suppliers for goods aggregating approximately $ 35,000 22,000

RELATED PARTY TRANSACTIONS

RELATED PARTY TRANSACTIONS	12 Months Ended
	Dec. 31, 2018
RELATED PARTY TRANSACTIONS	19. RELATED PARTY TRANSACTIONS Purchases from Carrier and its affiliates comprised 62% of all inventory purchases made during each of 2018, 2017 and 2016. At December 31, 2018 and 2017, approximately $71,000 and $75,000, respectively, was payable to Carrier and its affiliates, net of receivables. Our joint ventures with Carrier also sell HVAC products to Carrier and its affiliates. Revenues in our consolidated statements of income for 2018, 2017 and 2016 included approximately $84,000, $64,000 and $56,000, respectively, of sales to Carrier and its affiliates. We believe these transactions are conducted on terms equivalent to an arm’s-length basis in the ordinary course of business. A member of our Board of Directors is the Chairman and Chief Executive Officer of Moss & Associates LLC, which served as general contractor for the remodeling of our Miami headquarters that was completed in 2018. We paid Moss & Associates LLC $124, $951 and $291 for construction services performed during 2018, 2017 and 2016, respectively, and no amount was payable at December 31, 2018. A member of our Board of Directors is the Senior Chairman of Greenberg Traurig, P.A., which serves as our principal outside counsel and receives customary fees for legal services. During 2018 and 2017, we paid this firm $131 and $475, respectively, for services performed, and no amount was payable at December 31, 2018.

INFORMATION ABOUT GEOGRAPHIC AR

INFORMATION ABOUT GEOGRAPHIC AREAS	12 Months Ended
	Dec. 31, 2018
INFORMATION ABOUT GEOGRAPHIC AREAS	20. INFORMATION ABOUT GEOGRAPHIC AREAS Our operations are primarily within the United States, including Puerto Rico, Canada and Mexico. Products are also sold from the United States on an export-only basis to portions of Latin America and the Caribbean Basin. The following tables set forth revenues and long-lived assets by geographical area: Years Ended December 31, 2018 2017 2016 Revenues: United States $ 4,126,639 $ 3,919,684 $ 3,813,204 Canada 291,685 269,603 267,220 Mexico 128,329 152,668 140,278 Total revenues $ 4,546,653 $ 4,341,955 $ 4,220,702 December 31, 2018 2017 Long-Lived Assets: United States $ 550,939 $ 540,136 Canada 162,648 163,944 Mexico 5,640 5,400 Total long-lived assets $ 719,227 $ 709,480 Revenues are attributed to countries based on the location of the store from which the sale occurred. Long-lived assets consist primarily of goodwill and intangible assets, property and equipment, and our investment in an unconsolidated entity.

SUPPLEMENTAL CASH FLOW INFORMAT

SUPPLEMENTAL CASH FLOW INFORMATION	12 Months Ended
	Dec. 31, 2018
SUPPLEMENTAL CASH FLOW INFORMATION	21. SUPPLEMENTAL CASH FLOW INFORMATION Supplemental cash flow information was as follows: Years Ended December 31, 2018 2017 2016 Interest paid $ 3,065 $ 5,773 $ 3,362 Income taxes net of refunds $ 115,301 $ 48,056 $ 99,006 Common stock issued for Alert Labs Inc. $ 6,846 — —

SELECTED QUARTERLY FINANCIAL DA

SELECTED QUARTERLY FINANCIAL DATA	12 Months Ended
	Dec. 31, 2018
SELECTED QUARTERLY FINANCIAL DATA	WATSCO, INC. AND SUBSIDIARIES SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (In thousands, except per share data) 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Total Year Ended December 31, 2018 Revenues (1) $ 926,577 $ 1,332,743 $ 1,296,007 $ 991,326 $ 4,546,653 Gross profit $ 230,833 $ 320,766 $ 319,009 $ 249,644 $ 1,120,252 Net income attributable to Watsco, Inc. $ 34,219 $ 89,957 $ 79,163 $ 39,593 $ 242,932 Earnings per share for Common and Class B common stock (2): Basic $ 0.89 $ 2.41 $ 2.12 $ 1.02 $ 6.50 Diluted $ 0.89 $ 2.40 $ 2.11 $ 1.02 $ 6.49 Year Ended December 31, 2017 Revenues (1) $ 872,095 $ 1,275,924 $ 1,229,591 $ 964,345 $ 4,341,955 Gross profit $ 218,556 $ 310,278 $ 295,895 $ 240,930 $ 1,065,659 Net income attributable to Watsco, Inc. $ 26,181 $ 73,756 $ 65,029 $ 43,255 $ 208,221 Earnings per share for Common and Class B common stock (2): Basic $ 0.71 $ 2.07 $ 1.82 $ 1.19 $ 5.81 Diluted $ 0.71 $ 2.07 $ 1.82 $ 1.19 $ 5.81 (1) Sales of residential central air conditioners, heating equipment and parts and supplies are seasonal. Demand related to the residential central air conditioning replacement market is typically highest in the second and third quarters, and demand for heating equipment is usually highest in the fourth quarter. Demand related to the new construction sectors throughout most of the markets is fairly evenly distributed throughout the year except for dependence on housing completions and related weather and economic conditions. (2) Quarterly and year-to-date earnings per share are calculated on an individual basis; therefore, the sum of earnings per share amounts for the quarters may not equal earnings per share amounts for the year.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation	Organization, Consolidation and Presentation Watsco, Inc. (collectively with its subsidiaries, “Watsco,” “we,” “us,” or “our”) was incorporated in Florida in 1956 and is the largest distributor of air conditioning, heating and refrigeration equipment and related parts and supplies (“HVAC/R”) in the HVAC/R distribution industry in North America. At December 31, 2018, we operated from 571 locations in 37 U.S. states, Canada, Mexico, and Puerto Rico with additional market coverage on an export basis to portions of Latin America and the Caribbean. The consolidated financial statements include the accounts of Watsco, all of its wholly owned subsidiaries and the accounts of three joint ventures with Carrier Corporation (“Carrier”), in each of which Watsco maintains a controlling interest. All significant intercompany balances and transactions have been eliminated in consolidation.
Foreign Currency Translation and Transactions	Foreign Currency Translation and Transactions The functional currency of our operations in Canada is the Canadian dollar. Foreign currency denominated assets and liabilities are translated into U.S. dollars at the exchange rates in effect at the balance sheet date, and income and expense items are translated at the average exchange rates in effect during the applicable period. The aggregate effect of foreign currency translation is recorded in accumulated other comprehensive loss in our consolidated balance sheets. Our net investment in our Canadian operations is recorded at the historical rate and the resulting foreign currency translation adjustments are included in accumulated other comprehensive loss in our consolidated balance sheets. Gains or losses resulting from transactions denominated in U.S. dollars are recognized in earnings primarily within cost of sales in our consolidated statements of income. Our operations in Mexico consider their functional currency to be the U.S. dollar because the majority of their transactions are denominated in U.S. dollars. Gains or losses resulting from transactions denominated in Mexican pesos are recognized in earnings primarily within selling, general and administrative expenses in our consolidated statements of income.
Equity Method Investments	Equity Method Investments Investments in which we have the ability to exercise significant influence, but do not control, are accounted for under the equity method of accounting and are included in other assets in our consolidated balance sheets. Under this method of accounting, our proportionate share of the net income or loss of the investee is included in other income in our consolidated statements of income. The excess, if any, of the carrying amount of our investment over our ownership percentage in the underlying net assets of the investee is attributed to certain fair value adjustments with the remaining portion recognized as goodwill.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses for the reporting period. Significant estimates include valuation reserves for accounts receivable, inventories and income taxes, reserves related to loss contingencies and the valuation of goodwill, indefinite lived intangible assets and long-lived assets. While we believe that these estimates are reasonable, actual results could differ from such estimates.
Cash Equivalents	Cash Equivalents All highly liquid instruments purchased with original maturities of three months or less are considered to be cash equivalents.
Accounts Receivable and Allowance for Doubtful Accounts	Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable primarily consist of trade receivables due from customers and are stated at the invoiced amount less an allowance for doubtful accounts. An allowance for doubtful accounts is maintained for estimated losses resulting from the inability of customers to make required payments. When preparing these estimates, we consider a number of factors, including the aging of a customer’s account, past transactions with customers, creditworthiness of specific customers, historical trends and other information. Upon determination that an account is uncollectible, the receivable balance is written off. At December 31, 2018 and 2017, the allowance for doubtful accounts totaled $6,503 and $6,049, respectively.
Inventories	Inventories Inventories consist of air conditioning, heating and refrigeration equipment and related parts and supplies and are valued at the lower of cost using the weighted-average cost basis and the first-in, first-out methods, or net realizable value. As part of the valuation process, inventories are adjusted to reflect excess, slow-moving and damaged inventories at their estimated net realizable value. Inventory policies are reviewed periodically, reflecting current risks, trends and changes in industry conditions. A reserve for estimated inventory shrinkage is also maintained to consider inventory shortages determined from cycle counts and physical inventories.
Vendor Rebates	Vendor Rebates We have arrangements with several vendors that provide rebates payable to us when we achieve any of a number of measures, generally related to the volume level of purchases. We account for such rebates as a reduction of inventory until we sell the product, at which time such rebates are reflected as a reduction of cost of sales in our consolidated statements of income. Throughout the year, we estimate the amount of the rebate based on our estimate of purchases to date relative to the purchase levels that mark our progress toward earning the rebates. We continually revise our estimates of earned vendor rebates based on actual purchase levels. At December 31, 2018 and 2017, we had $11,603 and $11,621, respectively, of rebates recorded as a reduction of inventory. Substantially all vendor rebate receivables are collected within three months immediately following the end of the year.
Equity Securities	Equity Securities Investments in equity securities are recorded at fair value using the specific identification method and are included in other assets in our consolidated balance sheets. Unrealized holding gains and losses, net of deferred taxes, were included in accumulated other comprehensive loss within shareholders’ equity for 2017 and 2016. For 2018, changes in the fair value of equity securities were recognized through income rather than comprehensive income. Dividend and interest income are recognized in the statements of income when earned.
Property and Equipment	Property and Equipment Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization of property and equipment is computed using the straight-line method. Buildings and improvements are depreciated or amortized over estimated useful lives ranging from 3-40 years. Leasehold improvements are amortized over the shorter of the respective lease terms or estimated useful lives. Furniture and fixtures are depreciated over estimated useful lives ranging from 5-7 years. Estimated useful lives for other depreciable assets range from 3-10 years.
Goodwill and Other Intangible Assets	Goodwill and Intangible Assets Goodwill is recorded when the purchase price paid for an acquisition exceeds the fair value of the net identified tangible and intangible assets acquired. We evaluate goodwill for impairment annually or more frequently when an event occurs or circumstances change that indicate that the carrying value may not be recoverable. We test goodwill for impairment by first comparing the fair value of our reporting unit to its carrying value. If the fair value is determined to be less than the carrying value, a second step is performed to measure the amount of impairment loss. On January 1, 2019, we performed our annual evaluation of goodwill impairment and determined that the estimated fair value of our reporting unit significantly exceeded its carrying value. Intangible assets primarily consist of the value of trade names and trademarks, distributor agreements, customer relationships and . Indefinite lived intangibles not subject to amortization are assessed for impairment at least annually, or more frequently if events or changes in circumstances indicate they may be impaired, by comparing the fair value of the intangible asset to its carrying amount to determine if a write-down to fair value is required. Finite lived intangible assets are amortized using the straight-line method over their respective estimated useful lives. We perform our annual impairment tests each year and have determined there to be no impairment for any of the periods presented. There were no events or circumstances identified from the date of our assessment that would require an update to our annual impairment tests.
Long-Lived Assets	Long-Lived Assets Long-lived assets, other than goodwill and intangible assets, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. Recoverability is evaluated by determining whether the amortization of the balance over its remaining life can be recovered through undiscounted future operating cash flows. We measure the impairment loss based on projected discounted cash flows using a discount rate reflecting the average cost of funds and compared to the asset’s carrying value. As of December 31, 2018 there were no such events or circumstances.
Fair Value Measurements	Fair Value Measurements We carry various assets and liabilities at fair value in the consolidated balance sheets. Fair value is defined as the price that would be received for an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. Fair value measurements are classified based on the following fair value hierarchy: Level 1 Quoted prices in active markets for identical assets or liabilities. An active market for an asset or liability is a market in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2 Observable inputs other than Level 1 prices such as quoted prices in active markets for similar assets or liabilities; quoted prices in markets that are not active; or model-driven valuations or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 Unobservable inputs for the asset or liability. These inputs reflect our own assumptions about the assumptions a market participant would use in pricing the asset or liability.
Revenue Recognition	Revenue Recognition Revenue primarily consists of sales of air conditioning, heating and refrigeration equipment and related parts and supplies. We generate our revenue primarily from the sale of finished products to customers; therefore, the significant majority of our contracts are short-term in nature and have only a single performance obligation to deliver products; therefore, we satisfy our performance obligation under such contracts when we transfer control of the product to the customer. Some contracts contain a combination of product sales and services, the latter of which is distinct and accounted for as a separate performance obligation. We satisfy our performance obligations for services when we render the services within the agreed-upon service period. Total service revenue is not material and accounted for less than 1% of our consolidated revenues for 2018. Revenue is recognized when control transfers to our customers when picked up or via shipment of products or delivery of services. We measure revenue as the amount of consideration we expect to be entitled to receive in exchange for those goods or services, net of any variable considerations (e.g., rights to return product, sales incentives, others) and any taxes collected from customers and subsequently remitted to governmental authorities. Revenue for shipping and handling charges is recognized when products are delivered to the customer. Product Returns We estimate product returns based on historical experience and record them on a gross basis . Substantially all customer returns relate to products that are returned under manufacturers’ warranty obligations. Accrued sales returns of $11,275 at December 31, 2018 were included in accrued expenses and other current liabilities in our consolidated balance sheet. Sales Incentives We estimate sales incentives expected to be paid over the term of the program based on the most likely amounts. Sales incentives are accounted for as a reduction in the transaction price and are generally paid on an annual basis.
Advertising Costs	Advertising Costs Advertising costs are expensed as incurred. Advertising expense for the years ended December 31, 2018, 2017 and 2016, were $16,520, $24,677 and $22,242, respectively. See Note 2.
Shipping and Handling	Shipping and Handling Shipping and handling costs associated with inbound freight are capitalized to inventories and relieved through cost of sales as inventories are sold. Shipping and handling costs associated with the delivery of products is included in selling, general and administrative expenses. Shipping and handling costs included in selling, general and administrative expenses for the years ended December 31, 2018, 2017 and 2016, were $51,741, $47,670 and $42,809, respectively.
Share-Based Compensation	Share-Based Compensation The fair value of stock option and non-vested restricted stock awards are expensed net of estimated forfeitures on a straight-line basis over the vesting period of the awards. Share-based compensation expense is included in selling, general and administrative expenses in our consolidated statements of income. Tax benefits resulting from tax deductions in excess of share-based compensation expense are recognized in our provision for income taxes in our consolidated statements of income.
Income Taxes	Income Taxes We record U.S. federal, state and foreign income taxes currently payable, as well as deferred taxes due to temporary differences between reporting income and expenses for financial statement purposes versus tax purposes. Deferred tax assets and liabilities reflect the temporary differences between the financial statement and income tax basis of assets and liabilities. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of a change in tax rates is recognized as income or expense in the period that includes the enactment date. We and our eligible subsidiaries file a consolidated U.S. federal income tax return. As income tax returns are generally not filed until well after the closing process for the December 31 financial statements is complete, the amounts recorded at December 31 reflect estimates of what the final amounts will be when the actual income tax returns are filed for that calendar year. In addition, estimates are often required with respect to, among other things, the appropriate state income tax rates to use in the various states that we and our subsidiaries are required to file, the potential utilization of operating loss carryforwards and valuation allowances required, if any, for tax assets that may not be realizable in the future. We recognize the financial statement benefit of a tax position only after determining that the relevant tax authority would more likely than not sustain the position following an audit. For tax positions meeting the “more-likely-than-not” threshold, the amount recognized in the financial statements is the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement with the relevant tax authority.
Earnings per Share	Earnings per Share We compute earnings per share using the two-class method. The two-class method of computing earnings per share is an earnings allocation formula that determines earnings per share for common stock and any participating securities according to dividends declared (whether paid or unpaid) and participation rights in undistributed earnings. Shares of our non-vested restricted stock are considered participating securities because these awards contain a non-forfeitable right to dividends irrespective of whether the awards ultimately vest. Under the two-class method, earnings per common share for our Common and Class B common stock is computed by dividing the sum of distributed earnings to common shareholders and undistributed earnings allocated to common shareholders by the weighted-average number of shares of Common and Class B common stock outstanding for the period. In applying the two-class method, undistributed earnings are allocated to Common stock, Class B common stock and participating securities based on the weighted-average shares outstanding during the period. Diluted earnings per share reflects the dilutive effect of potential common shares from stock options. The dilutive effect of outstanding stock options is computed using the treasury stock method, which assumes any proceeds that could be obtained upon the exercise of stock options, would be used to purchase common stock at the average market price for the period. The assumed proceeds include the purchase price the optionee pays, the windfall tax benefit that we receive upon assumed exercise and the unrecognized compensation expense at the end of each period.
Derivative Instruments and Hedging Activity	Derivative Instruments and Hedging Activity We have used derivative instruments, including forward and option contracts and swaps, to manage our exposure to fluctuations in foreign currency exchange rates and interest rates. The use of these derivative instruments modifies the exposure of these risks with the intent to reduce the risk or cost to us. We use derivative instruments as risk management tools and not for trading purposes. All derivatives, whether designated as hedging relationships or not, are recorded on the balance sheet at fair value. Cash flows from derivative instruments are classified in the consolidated statements of cash flows in the same category as the cash flows from the items subject to the designated hedge or undesignated (economic) hedge relationships. The hedging designation may be classified as one of the following: No Hedging Designation. The gain or loss on a derivative instrument not designated as an accounting hedging instrument is recognized in earnings within selling, general and administrative expenses. Cash Flow Hedge. A hedge of a forecasted transaction or of the variability of cash flows to be received or paid related to a recognized asset or liability is considered a cash flow hedge. The effective portion of the change in the fair value of a derivative that is designated as a cash flow hedge is recorded in other comprehensive income and reclassified to earnings as a component of cost of sales in the period for which the hedged transaction affects earnings. Ineffective portions of changes in the fair value of cash flow hedges are recognized in earnings. Fair Value Hedge. A hedge of a recognized asset or liability or an unrecognized firm commitment is considered a fair value hedge. Fair value hedges, both the effective and ineffective portions of the changes in the fair value of the derivative, along with the gain or loss on the hedged item that is attributable to the hedged risk, are recorded in earnings. See Note 16 for additional information pertaining to derivative instruments.
Loss Contingencies	Loss Contingencies Accruals are recorded for various contingencies including self-insurance, legal proceedings, environmental matters, and other claims that arise in the normal course of business. The estimation process contains uncertainty because accruals are based on judgment, the probability of losses and, where applicable, the consideration of opinions of external legal counsel and actuarially determined estimates. Additionally, we record receivables from third party insurers when recovery has been determined to be probable.
Recently Adopted Accounting Standards and Recently Issued Accounting Standards Not Yet Adopted	Recently Adopted Accounting Standards Revenue Recognition In May 2014, the Financial Accounting Standards Board (the “FASB”) issued a standard on revenue recognition that provides a single, comprehensive revenue recognition model for all contracts with customers. The standard is principle-based and provides a five-step model to determine the measurement of revenue and timing of when it is recognized. In 2015 and 2016, the FASB issued several updates to this standard. The adoption of this standard and its related amendments (collectively, the “New Revenue Standard”) on January 1, 2018 did not result in the recognition of a cumulative adjustment to opening retained earnings under the modified retrospective approach, nor did it have a significant impact on our consolidated net income, balance sheet or cash flow. See Note 2. Financial Instruments In January 2016, the FASB issued guidance related to certain aspects of recognition, measurement, presentation and disclosure of financial instruments. Most prominent among the changes to the standard is the requirement that changes in the fair value of equity investments, with certain exceptions, be recognized through net income rather than other comprehensive income. This guidance must be applied using a modified retrospective approach through a cumulative-effect adjustment to retained earnings and became effective for interim and annual periods beginning after December 15, 2017. The adoption of this guidance did not have a material impact on our consolidated financial statements. A cumulative-effect adjustment captured the previously held unrealized losses of $301 related to our equity securities carried at fair value. See Note 4. Stock Compensation In May 2017, the FASB issued guidance to clarify when to account for a change to the terms or conditions of a share-based payment award as a modification. Under the new guidance, modification accounting is required only if the fair value, the vesting conditions or the classification of the award (as equity or liability) changes as a result of the change in terms or conditions. This guidance must be applied prospectively and became effective for interim and annual periods beginning after December 15, 2017. The adoption of this guidance did not have a material impact on our consolidated financial statements. Derivatives and Hedging In August 2017, the FASB issued guidance to simplify the accounting for hedging derivatives. This guidance is effective prospectively and is effective for interim and annual periods beginning after December 15, 2018 with early adoption permitted. We elected to adopt this guidance during the quarter ended June 30, 2018, which did not have a material impact on our consolidated financial statements. Recently Issued Accounting Standards Not Yet Adopted Leases In February 2016, the FASB issued guidance on accounting for leases, which requires lessees to recognize most leases on their balance sheets for the rights and obligations created by those leases. In July 2018, updated guidance was issued which provides an additional transition method of adoption that allows entities to initially apply the standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings. We adopted this standard and its related amendments (collectively, the “New Lease Standard”) on January 1, 2019, using this additional transition method, and we have elected the available practical expedients upon adoption. Although we continue to evaluate the impact of the New Lease Standard on our consolidated balance sheet, we do not expect that it will have a material impact on our consolidated statements of income. Following adoption of the New Lease Standard, we record a right-of-use (“ROU”) asset and lease liability, representing our obligation to make lease payments for operating leases greater than one year in duration, measured on a discounted basis. We expect that the ROU asset and lease liability recorded will be approximately 10% of our total assets. In preparation for the adoption, we are implementing business processes and controls over the financial reporting of leases, which will facilitate our reporting under the New Lease Standard in the first quarter of 2019. See Note 18, under the caption “Operating Leases,” for our minimum lease commitments at December 31, 2018. Intangibles—Goodwill and Other In January 2017, the FASB issued guidance to simplify the subsequent measurement of goodwill by eliminating Step 2 from the goodwill impairment test. Under this updated standard, an entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, but the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. An entity also should consider income tax effects from any tax-deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if any. This guidance is effective prospectively and is effective for interim and annual periods beginning after December 15, 2019 with early adoption permitted. We do not expect the adoption of this guidance to have a material impact on our consolidated financial statements. Disclosure Update and Simplification In August 2018, the Securities and Exchange Commission (“SEC”) issued the final rule under SEC Release No. 33-10532, “Disclosure Update and Simplification,” that amends certain of its disclosure requirements that have become redundant, duplicative, overlapping, outdated or superseded. The amendments include removing the requirement to disclose information on geographic regions from the Description of Business section of Form 10-K and replacing the requirement that a registrant disclose the high and low trading prices of entity’s ordinary shares with a requirement to disclose the ticker symbol of its shares. Additionally, the final rule extends to interim periods the annual disclosure requirement of presenting changes in each caption of stockholders’ equity and the amount of dividends per share. These disclosures are required to be provided for the current and comparative year-to-date interim periods. The final rule is effective for all filings on or after November 5, 2018. We have adopted all relevant disclosure requirements for our Annual Report on Form 10-K for the year ended December 31, 2018.

REVENUES (Tables)

REVENUES (Tables)	12 Months Ended
	Dec. 31, 2018
Summary of Disaggregated Revenue	The following table presents our revenues disaggregated by primary geographical regions and major product lines within our single reporting segment: Years Ended December 31, 2018 2017(1) 2016(1) Primary Geographical Regions: United States $ 4,126,639 $ 3,919,684 $ 3,813,204 Canada 291,685 269,603 267,220 Mexico 128,329 152,668 140,278 $ 4,546,653 $ 4,341,955 $ 4,220,702 Major Product Lines: HVAC equipment 67 % 67 % 66 % Other HVAC products 29 % 28 % 29 % Commercial refrigeration products 4 % 5 % 5 % 100 % 100 % 100 % (1) As noted above, prior period amounts have not been adjusted under the modified retrospective method and remain as originally reported for such periods.

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2018
Schedule of Basic and Diluted Earnings Per Common Share	The following table presents the calculation of basic and diluted earnings per share for our Common and Class B common stock: Years Ended December 31, 2018 2017 2016 Basic Earnings per Share: Net income attributable to Watsco, Inc. shareholders $ 242,932 $ 208,221 $ 182,810 Less: distributed and undistributed earnings allocated to non-vested restricted common stock 19,792 17,430 14,806 Earnings allocated to Watsco, Inc. shareholders $ 223,140 $ 190,791 $ 168,004 Weighted-average common shares outstanding - Basic 34,319,890 32,824,947 32,582,385 Basic earnings per share for Common and Class B common stock $ 6.50 $ 5.81 $ 5.16 Allocation of earnings for Basic: Common stock $ 206,355 $ 175,667 $ 154,021 Class B common stock 16,785 15,124 13,983 $ 223,140 $ 190,791 $ 168,004 Diluted Earnings per Share: Net income attributable to Watsco, Inc. shareholders $ 242,932 $ 208,221 $ 182,810 Less: distributed and undistributed earnings allocated to non-vested restricted common stock 19,788 17,427 14,801 Earnings allocated to Watsco, Inc. shareholders $ 223,144 $ 190,794 $ 168,009 Weighted-average common shares outstanding - Basic 34,319,890 32,824,947 32,582,385 Effect of dilutive stock options 54,379 37,686 34,119 Weighted-average common shares outstanding - Diluted 34,374,269 32,862,633 32,616,504 Diluted earnings per share for Common and Class B common stock $ 6.49 $ 5.81 $ 5.15

OTHER COMPREHENSIVE (LOSS) IN_2

OTHER COMPREHENSIVE (LOSS) INCOME (Tables)	12 Months Ended
	Dec. 31, 2018
Schedule of Tax Effects Allocated to Each Component of Other Comprehensive Income (Loss)	The tax effects allocated to each component of other comprehensive income (loss) were as follows: Years Ended December 31, 2018 2017 2016 Foreign currency translation adjustment $ (20,493 ) $ 15,993 $ 6,211 Unrealized gain (loss) on cash flow hedging instruments 2,627 (961 ) (1,321 ) Income tax (expense) benefit (709 ) 259 356 Unrealized gain (loss) on cash flow hedging instruments, net of tax 1,918 (702 ) (965 ) Reclassification of (gain) loss on cash flow hedging instruments into earnings (215 ) (491 ) 442 Income tax expense (benefit) 58 133 (119 ) Reclassification of (gain) loss on cash flow hedging instruments into earnings, net of tax (157 ) (358 ) 323 Unrealized gain on equity securities — 51 27 Income tax expense — (66 ) (13 ) Unrealized (loss) gain on equity securities, net of tax — (15 ) 14 Other comprehensive (loss) income $ (18,732 ) $ 14,918 $ 5,583
Schedule of Accumulated Other Comprehensive Loss	The changes in each component of accumulated other comprehensive loss, net of tax, were as follows: Years Ended December 31, 2018 2017 2016 Foreign currency translation adjustment: Beginning balance $ (33,499 ) $ (43,459 ) $ (47,204 ) Current period other comprehensive (loss) income (13,105 ) 9,960 3,745 Ending balance (46,604 ) (33,499 ) (43,459 ) Cash flow hedging instruments: Beginning balance (421 ) 215 600 Current period other comprehensive income (loss) 1,151 (421 ) (579 ) Reclassification adjustment (94 ) (215 ) 194 Ending balance 636 (421 ) 215 Equity securities: Beginning balance (301 ) (286 ) (300 ) Cumulative-effect adjustment to retained earnings 301 — — Current period other comprehensive (loss) income — (15 ) 14 Ending balance — (301 ) (286 ) Accumulated other comprehensive loss, net of tax $ (45,968 ) $ (34,221 ) $ (43,530 )

PROPERTY AND EQUIPMENT (Tables)

PROPERTY AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2018
Property and Equipment, Net	Property and equipment, net, consists of: December 31, 2018 2017 Land $ 820 $ 820 Buildings and improvements 75,308 74,486 Machinery, vehicles and equipment 79,002 76,117 Furniture and fixtures 16,782 15,282 Computer hardware and software 50,853 47,377 222,765 214,082 Accumulated depreciation and amortization (131,719 ) (122,884 ) $ 91,046 $ 91,198 Depreciation and amortization expense related to property and equipment included in selling, general and administrative expenses for the years ended December 31, 2018, 2017 and 2016, were $16,747, $16,770 and $14,853, respectively.

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2018
Components of Income Tax Expense	The components of income tax expense from our wholly owned operations and investments and our controlling interest in joint ventures with Carrier are as follows: Years Ended December 31, 2018 2017 2016 U.S. Federal $ 54,345 $ 69,079 $ 86,719 State 11,631 10,643 9,801 Foreign 6,837 10,499 9,416 $ 72,813 $ 90,221 $ 105,936 Current $ 64,523 $ 100,956 $ 103,216 Deferred 8,290 (10,735 ) 2,720 $ 72,813 $ 90,221 $ 105,936
Reconciliation of Effective Income Tax Rate	Following is a reconciliation of the effective income tax rate: Years Ended December 31, 2018 2017 2016 U.S. federal statutory rate 21.0 % 35.0 % 35.0 % State income taxes, net of federal benefit and other 3.6 2.4 2.3 Excess tax benefits from share-based compensation (2.0 ) (2.7 ) (1.0 ) Tax effects on foreign income 0.5 (1.0 ) (0.1 ) GILTI 0.3 — — Tax credits and other — (0.6 ) (0.2 ) Repatriation transition tax (0.9 ) 3.0 — Deferred tax impact of enacted tax rate changes 0.3 (6.3 ) — Effective income tax rate attributable to Watsco, Inc. 22.8 29.8 36.0 Taxes attributable to non-controlling interest (3.1 ) (3.8 ) (5.0 ) Effective income tax rate 19.7 % 26.0 % 31.0 %
Significant Components of Net Deferred Tax Liabilities	The following is a summary of the significant components of our net deferred tax liabilities: December 31, 2018 2017 Deferred tax assets: Share-based compensation $ 21,517 $ 18,977 Capitalized inventory costs and inventory reserves 2,151 2,107 Allowance for doubtful accounts 1,057 929 Self-insurance reserves 206 153 Other 2,486 2,423 Net operating loss carryforwards 484 291 27,901 24,880 Valuation allowance — — Total deferred tax assets 27,901 24,880 Deferred tax liabilities: Deductible goodwill (69,600 ) (67,246 ) Depreciation (10,695 ) (5,519 ) Other (8,516 ) (5,189 ) Total deferred tax liabilities (88,811 ) (77,954 ) Net deferred tax liabilities (1) $ (60,910 ) $ (53,074 ) (1) Net deferred tax liabilities have been included in the consolidated balance sheets in deferred income taxes and other liabilities.
Changes in Gross Unrecognized Tax Benefits	The changes in gross unrecognized tax benefits are as follows: Balance at December 31, 2015 $ 3,513 Additions based on tax positions related to the current year 547 Reductions due to lapse of applicable statute of limitations and tax assessments (365 ) Balance at December 31, 2016 3,695 Additions based on tax positions related to the current year 801 Reductions due to lapse of applicable statute of limitations (271 ) Balance at December 31, 2017 4,225 Additions based on tax positions related to the current year 960 Reductions due to lapse of applicable statute of limitations (283 ) Balance at December 31, 2018 $ 4,902

SHARE-BASED COMPENSATION AND _2

SHARE-BASED COMPENSATION AND BENEFIT PLANS (Tables)	12 Months Ended
	Dec. 31, 2018
Summary of Stock Option Activity	The following is a summary of stock option activity under the 2014 Plan and the 2001 Plan as of and for the year ended December 31, 2018: Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Options outstanding at December 31, 2017 398,833 $ 136.44 Granted 188,550 173.48 Exercised (54,934 ) 114.09 Forfeited (26,832 ) 155.83 Expired (1,000 ) 122.62 Options outstanding at December 31, 2018 504,617 $ 151.71 3.31 $ 1,733 Options exercisable at December 31, 2018 71,487 $ 135.89 2.13 $ 826
Summary of Non-Vested Restricted Stock Activity	The following is a summary of non-vested restricted stock activity as of and for the year ended December 31, 2018: Shares Weighted- Average Grant Date Fair Value Non-vested restricted stock outstanding at December 31, 2017 2,985,239 $ 51.22 Granted 142,865 167.06 Vested (55,502 ) 66.52 Forfeited (10,000 ) 142.52 Non-vested restricted stock outstanding at December 31, 2018 3,062,602 $ 48.72
Valuation Assumptions Used for Stock Option Awards	The following table presents the weighted-average assumptions used for stock options granted: Years Ended December 31, 2018 2017 2016 Expected term in years 4.25 4.25 4.25 Risk-free interest rate 2.69 % 1.77 % 1.24 % Expected volatility 17.11 % 17.41 % 18.65 % Expected dividend yield 3.13 % 2.82 % 2.54 % Grant date fair value $ 20.05 $ 17.23 $ 16.37
Share-Based Compensation Expense	The following table provides information on share-based compensation expense: Years Ended December 31, 2018 2017 2016 Stock options $ 2,014 $ 1,451 $ 1,149 Non-vested restricted stock 13,494 11,842 11,170 Share-based compensation expense $ 15,508 $ 13,293 $ 12,319

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS (Tables)	12 Months Ended
	Dec. 31, 2018
Changes in Carrying Amount of Goodwill	The changes in the carrying amount of goodwill are as follows: Balance at December 31, 2016 $ 379,737 Foreign currency translation adjustment 2,992 Balance at December 31, 2017 382,729 Acquired goodwill 13,301 Foreign currency translation adjustment (4,032 ) Balance at December 31, 2018 $ 391,998
Indefinite Lived Intangible Assets	Intangible assets are comprised of the following: December 31, Estimated Useful Lives 2018 2017 Indefinite lived intangible assets - Trade names, trademarks and distribution rights $ 119,188 $ 125,194 Finite lived intangible assets: Customer relationships 10-15 years 69,593 73,053 Patented and unpatented technology 7 1,600 — Trade name 10 years 1,150 1,150 Accumulated amortization (43,680 ) (38,332 ) Finite lived intangible assets, net 28,663 35,871 $ 147,851 $ 161,065
Finite lived intangible assets	Intangible assets are comprised of the following: December 31, Estimated Useful Lives 2018 2017 Indefinite lived intangible assets - Trade names, trademarks and distribution rights $ 119,188 $ 125,194 Finite lived intangible assets: Customer relationships 10-15 years 69,593 73,053 Patented and unpatented technology 7 1,600 — Trade name 10 years 1,150 1,150 Accumulated amortization (43,680 ) (38,332 ) Finite lived intangible assets, net 28,663 35,871 $ 147,851 $ 161,065
Amortization Expense Related to Finite Lived Intangible Assets	Annual amortization of finite lived intangible assets for the next five years is expected to approximate the following: 2019 $ 5,000 2020 $ 5,000 2021 $ 4,200 2022 $ 3,400 2023 $ 2,800

DERIVATIVES (Tables)

DERIVATIVES (Tables)	12 Months Ended
	Dec. 31, 2018
Impact from Foreign Exchange Derivative Instruments Designated as Cash Flow Hedges	The impact from foreign exchange derivative instruments designated as cash flow hedges was as follows: Years Ended December 31, 2018 2017 Gain (loss) recorded in accumulated other comprehensive loss $ 2,627 $ (961 ) (Gain) l oss reclassified from accumulated other comprehensive loss into earnings $ (215 ) $ (491 )
Fair Value of Derivative Instruments and Location in the Balance Sheets	The following table summarizes the fair value of derivative instruments, which consist solely of foreign exchange contracts, included in other current assets and accrued expenses and other current liabilities in our consolidated balance sheets. See Note 17. Asset Derivatives Liability Derivatives December 31, 2018 2017 2018 2017 Derivatives designated as hedging instruments $ 1,262 $ 70 $ 3 $ 773 Derivatives not designated as hedging instruments 58 180 11 184 Total derivative instruments $ 1,320 $ 250 $ 14 $ 957

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2018
Assets and Liabilities Measured at Fair Value on Recurring Basis	The following tables present our assets and liabilities carried at fair value that are measured on a recurring basis: Fair Value Measurements at December 31, 2018 Using Balance Sheet Location Total Level 1 Level 2 Level 3 Assets: Derivative financial instruments Other current assets $ 1,320 — $ 1,320 — Equity securities Other assets $ 279 $ 279 — — Liabilities: Derivative financial instruments Accrued expenses and other current liabilities $ 14 — $ 14 — Fair Value Measurements at December 31, 2017 Using Balance Sheet Location Total Level 1 Level 2 Level 3 Assets: Derivative financial instruments Other current assets $ 250 — $ 250 — Equity securities Other assets $ 332 $ 332 — — Liabilities: Derivative financial instruments Accrued expenses and other current liabilities $ 957 — $ 957 —

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2018
Future Minimum Lease Payments under Non-Cancelable Operating Leases	At December 31, 2018, future minimum payments under non-cancelable operating leases over each of the next five years and thereafter were as follows: 2019 $ 70,388 2020 55,102 2021 41,321 2022 28,482 2023 15,712 Thereafter 8,245 Total minimum payments $ 219,250

INFORMATION ABOUT GEOGRAPHIC _2

INFORMATION ABOUT GEOGRAPHIC AREAS (Tables)	12 Months Ended
	Dec. 31, 2018
Revenues and Long-Lived Assets by Geographical Area	The following tables set forth revenues and long-lived assets by geographical area: Years Ended December 31, 2018 2017 2016 Revenues: United States $ 4,126,639 $ 3,919,684 $ 3,813,204 Canada 291,685 269,603 267,220 Mexico 128,329 152,668 140,278 Total revenues $ 4,546,653 $ 4,341,955 $ 4,220,702 December 31, 2018 2017 Long-Lived Assets: United States $ 550,939 $ 540,136 Canada 162,648 163,944 Mexico 5,640 5,400 Total long-lived assets $ 719,227 $ 709,480

SUPPLEMENTAL CASH FLOW INFORM_2

SUPPLEMENTAL CASH FLOW INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2018
Supplemental Cash Flow Information	Supplemental cash flow information was as follows: Years Ended December 31, 2018 2017 2016 Interest paid $ 3,065 $ 5,773 $ 3,362 Income taxes net of refunds $ 115,301 $ 48,056 $ 99,006 Common stock issued for Alert Labs Inc. $ 6,846 — —

SELECTED QUARTERLY FINANCIAL _2

SELECTED QUARTERLY FINANCIAL DATA (Tables)	12 Months Ended
	Dec. 31, 2018
Selected Quarterly Financial Data	WATSCO, INC. AND SUBSIDIARIES SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (In thousands, except per share data) 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Total Year Ended December 31, 2018 Revenues (1) $ 926,577 $ 1,332,743 $ 1,296,007 $ 991,326 $ 4,546,653 Gross profit $ 230,833 $ 320,766 $ 319,009 $ 249,644 $ 1,120,252 Net income attributable to Watsco, Inc. $ 34,219 $ 89,957 $ 79,163 $ 39,593 $ 242,932 Earnings per share for Common and Class B common stock (2): Basic $ 0.89 $ 2.41 $ 2.12 $ 1.02 $ 6.50 Diluted $ 0.89 $ 2.40 $ 2.11 $ 1.02 $ 6.49 Year Ended December 31, 2017 Revenues (1) $ 872,095 $ 1,275,924 $ 1,229,591 $ 964,345 $ 4,341,955 Gross profit $ 218,556 $ 310,278 $ 295,895 $ 240,930 $ 1,065,659 Net income attributable to Watsco, Inc. $ 26,181 $ 73,756 $ 65,029 $ 43,255 $ 208,221 Earnings per share for Common and Class B common stock (2): Basic $ 0.71 $ 2.07 $ 1.82 $ 1.19 $ 5.81 Diluted $ 0.71 $ 2.07 $ 1.82 $ 1.19 $ 5.81 (1) Sales of residential central air conditioners, heating equipment and parts and supplies are seasonal. Demand related to the residential central air conditioning replacement market is typically highest in the second and third quarters, and demand for heating equipment is usually highest in the fourth quarter. Demand related to the new construction sectors throughout most of the markets is fairly evenly distributed throughout the year except for dependence on housing completions and related weather and economic conditions. (2) Quarterly and year-to-date earnings per share are calculated on an individual basis; therefore, the sum of earnings per share amounts for the quarters may not equal earnings per share amounts for the year.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018USD ($)StoreStateEntity	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Significant Accounting Policies [Line Items]
Number of joint ventures | Entity	3
Allowance for doubtful accounts	$ 6,503,000	$ 6,049,000
Capitalized vendor rebates	11,603,000	11,621,000
Goodwill and intangible assets impairment	0	0	$ 0
Accrued sales returns included in accrued expenses and other current liabilities	11,275,000
Cumulative-effect adjustment to retained earnings	301,000
Selling, general and administrative expense	$ 757,452,000	715,671,000	688,952,000
Assets, Total [Member]
Significant Accounting Policies [Line Items]
Percentage of Right Of Use Assets and Lease Liability	10.00%
Shipping and Handling [Member]
Significant Accounting Policies [Line Items]
Selling, general and administrative expense	$ 51,741,000	47,670,000	42,809,000
Advertising Expense [Member]
Significant Accounting Policies [Line Items]
Selling, general and administrative expense	$ 16,520,000	$ 24,677,000	$ 22,242,000
Minimum | Buildings and Improvements
Significant Accounting Policies [Line Items]
Estimated useful lives in years	3 years
Minimum | Other Depreciable Assets
Significant Accounting Policies [Line Items]
Estimated useful lives in years	3 years
Minimum | Furniture and Fixtures
Significant Accounting Policies [Line Items]
Estimated useful lives in years	5 years
Maximum | Sales Revenue, Net [Member] | Product Concentration Risk
Significant Accounting Policies [Line Items]
Percentage of Service Revenue	1.00%
Maximum | Buildings and Improvements
Significant Accounting Policies [Line Items]
Estimated useful lives in years	40 years
Maximum | Other Depreciable Assets
Significant Accounting Policies [Line Items]
Estimated useful lives in years	10 years
Maximum | Furniture and Fixtures
Significant Accounting Policies [Line Items]
Estimated useful lives in years	7 years
Watsco, Inc.
Significant Accounting Policies [Line Items]
Number of locations from which entity operates | Store	571
Number of states in which entity operates | State	37

Summary of Disaggregated Revenu

Summary of Disaggregated Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2018	[1]	Sep. 30, 2018	[1]	Jun. 30, 2018	[1]	Mar. 31, 2018	[1]	Dec. 31, 2017	[1]	Sep. 30, 2017	[1]	Jun. 30, 2017	[1]	Mar. 31, 2017	[1]	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Revenues from product lines, percentage																	100.00%	100.00%	100.00%
Revenues	$ 991,326		$ 1,296,007		$ 1,332,743		$ 926,577		$ 964,345		$ 1,229,591		$ 1,275,924		$ 872,095		$ 4,546,653	$ 4,341,955	$ 4,220,702
United States
Disaggregation of Revenue [Line Items]
Revenues																	4,126,639	3,919,684	3,813,204
Canada
Disaggregation of Revenue [Line Items]
Revenues																	291,685	269,603	267,220
Mexico
Disaggregation of Revenue [Line Items]
Revenues																	$ 128,329	$ 152,668	$ 140,278
HVAC Equipment
Disaggregation of Revenue [Line Items]
Revenues from product lines, percentage																	67.00%	67.00%	66.00%
Other HVAC Products
Disaggregation of Revenue [Line Items]
Revenues from product lines, percentage																	29.00%	28.00%	29.00%
Commercial Refrigeration Products
Disaggregation of Revenue [Line Items]
Revenues from product lines, percentage																	4.00%	5.00%	5.00%
[1]	Sales of residential central air conditioners, heating equipment and parts and supplies are seasonal. Demand related to the residential central air conditioning replacement market is typically highest in the second and third quarters, and demand for heating equipment is usually highest in the fourth quarter. Demand related to the new construction sectors throughout most of the markets is fairly evenly distributed throughout the year except for dependence on housing completions and related weather and economic conditions.

Schedule of Basic and Diluted E

Schedule of Basic and Diluted Earnings per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2018		Sep. 30, 2018		Jun. 30, 2018		Mar. 31, 2018		Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income attributable to Watsco, Inc. shareholders	$ 39,593		$ 79,163		$ 89,957		$ 34,219		$ 43,255		$ 65,029		$ 73,756		$ 26,181		$ 242,932		$ 208,221		$ 182,810
Less: distributed and undistributed earnings allocated to non-vested restricted common stock - Basic																	19,792		17,430		14,806
Earnings allocated to Watsco, Inc. shareholders - Basic																	$ 223,140		$ 190,791		$ 168,004
Weighted-average common shares outstanding - Basic																	34,319,890		32,824,947		32,582,385
Basic earnings per share for Common and Class B common stock	$ 1.02	[1]	$ 2.12	[1]	$ 2.41	[1]	$ 0.89	[1]	$ 1.19	[1]	$ 1.82	[1]	$ 2.07	[1]	$ 0.71	[1]	$ 6.50	[1]	$ 5.81	[1]	$ 5.16
Net income attributable to Watsco, Inc. shareholders	$ 39,593		$ 79,163		$ 89,957		$ 34,219		$ 43,255		$ 65,029		$ 73,756		$ 26,181		$ 242,932		$ 208,221		$ 182,810
Less: distributed and undistributed earnings allocated to non-vested restricted common stock - Diluted																	19,788		17,427		14,801
Earnings allocated to Watsco, Inc. shareholders - Diluted																	$ 223,144		$ 190,794		$ 168,009
Weighted-average common shares outstanding - Basic																	34,319,890		32,824,947		32,582,385
Effect of dilutive stock options																	54,379		37,686		34,119
Weighted-average common shares outstanding - Diluted																	34,374,269		32,862,633		32,616,504
Diluted earnings per share for Common and Class B common stock	$ 1.02	[1]	$ 2.11	[1]	$ 2.40	[1]	$ 0.89	[1]	$ 1.19	[1]	$ 1.82	[1]	$ 2.07	[1]	$ 0.71	[1]	$ 6.49	[1]	$ 5.81	[1]	$ 5.15
Common Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Earnings allocated to Watsco, Inc. shareholders - Basic																	$ 206,355		$ 175,667		$ 154,021
Class B Common Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Earnings allocated to Watsco, Inc. shareholders - Basic																	$ 16,785		$ 15,124		$ 13,983
[1]	Quarterly and year-to-date earnings per share are calculated on an individual basis; therefore, the sum of earnings per share amounts for the quarters may not equal earnings per share amounts for the year.

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Detail) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Line Items]
Class B common stock conversion, number of shares	2,581,627	2,601,996	2,711,811
Anti-dilutive stock options excluded from earnings per share	74,270	11,664	31,839

Schedule of Tax Effects Allocat

Schedule of Tax Effects Allocated to Each Component of Other Comprehensive (Loss) Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Components Of Other Comprehensive Income Loss [Line Items]
Foreign currency translation adjustment	$ (20,493)	$ 15,993	$ 6,211
Unrealized gain (loss) on cash flow hedging instruments	2,627	(961)	(1,321)
Income tax (expense) benefit	(709)	259	356
Unrealized gain (loss) on cash flow hedging instruments, net of tax	1,918	(702)	(965)
Reclassification of (gain) loss on cash flow hedging instruments into earnings	(215)	(491)	442
Income tax expense (benefit)	58	133	(119)
Reclassification of (gain) loss on cash flow hedging instruments into earnings, net of tax	(157)	(358)	323
Unrealized gain on equity securities		51	27
Income tax expense		(66)	(13)
Unrealized (loss) gain on equity securities, net of tax		(15)	14
Other comprehensive (loss) income	$ (18,732)	$ 14,918	$ 5,583

Schedule of Accumulated Other C

Schedule of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (34,221)	$ (43,530)
Cumulative-effect adjustment to retained earnings	301
Ending balance	(45,968)	(34,221)	$ (43,530)
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(33,499)	(43,459)	(47,204)
Current period other comprehensive income (loss)	(13,105)	9,960	3,745
Ending balance	(46,604)	(33,499)	(43,459)
Cash Flow Hedging Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(421)	215	600
Current period other comprehensive income (loss)	1,151	(421)	(579)
Reclassification adjustment	(94)	(215)	194
Ending balance	636	(421)	215
Equity Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(301)	(286)	(300)
Cumulative-effect adjustment to retained earnings	$ 301
Current period other comprehensive income (loss)		(15)	14
Ending balance		$ (301)	$ (286)

Supplier Concentration - Additi

Supplier Concentration - Additional Information (Detail) - Supplier Concentration Risk - Vendor	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Concentration Risk [Line Items]
Number of key suppliers	10
Cost of Goods, Total
Concentration Risk [Line Items]
Percentage of purchases from key suppliers	84.00%	84.00%	85.00%
Carrier and Its Affiliates | Cost of Goods, Total
Concentration Risk [Line Items]
Percentage of purchases from key suppliers	62.00%	62.00%	62.00%

Property and Equipment, Net (De

Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 222,765	$ 214,082
Accumulated depreciation and amortization	(131,719)	(122,884)
Property and equipment, net	91,046	91,198
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	820	820
Buildings and Improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	75,308	74,486
Machinery, Vehicles and Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	79,002	76,117
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	16,782	15,282
Computer Hardware and Software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 50,853	$ 47,377

Property and Equipment - Additi

Property and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 16,747	$ 16,770	$ 14,853

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($)	Dec. 05, 2018	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Revolving credit agreement, maturity date	Dec. 5, 2023
Proceeds from credit facility	$ 54,700,000
Payment of fees related to revolving credit agreement			$ 790,000
Borrowings under revolving credit agreement			135,200,000	$ 21,800,000
Swingline Subfacility
Debt Instrument [Line Items]
Maximum capacity under revolving credit agreement			100,000,000
Letter of Credit
Debt Instrument [Line Items]
Maximum capacity under revolving credit agreement			10,000,000
Revolving Credit Facility
Debt Instrument [Line Items]
Payment of fees related to revolving credit agreement			790,000
Maximum capacity under revolving credit agreement	$ 500,000,000			$ 300,000,000
Maturing Term	5 years			5 years
Seasonal discretionary maximum borrowing capacity under revolving credit agreement		$ 400,000,000
Alternative Currency Sublimit
Debt Instrument [Line Items]
Maximum capacity under revolving credit agreement			75,000,000
Mexican Borrowing Sublimit
Debt Instrument [Line Items]
Maximum capacity under revolving credit agreement			$ 8,000,000
London Interbank Offer Rate
Debt Instrument [Line Items]
Basis spread			87.50%
London Interbank Offer Rate | Minimum
Debt Instrument [Line Items]
Basis spread			87.50%
London Interbank Offer Rate | Maximum
Debt Instrument [Line Items]
Basis spread			150.00%
Federal Funds Effective Rate [Member]
Debt Instrument [Line Items]
Basis spread			0.50%
Federal Funds Effective Rate [Member] | Minimum
Debt Instrument [Line Items]
Basis spread			0.00%
Federal Funds Effective Rate [Member] | Maximum
Debt Instrument [Line Items]
Basis spread			0.50%
Eurocurrency Rate
Debt Instrument [Line Items]
Basis spread			1.00%
Eurocurrency Rate | Minimum
Debt Instrument [Line Items]
Basis spread			0.00%
Eurocurrency Rate | Maximum
Debt Instrument [Line Items]
Basis spread			50.00%
Commitment Fee
Debt Instrument [Line Items]
Basis spread			7.50%
Commitment Fee | Minimum
Debt Instrument [Line Items]
Basis spread			7.50%
Commitment Fee | Maximum
Debt Instrument [Line Items]
Basis spread			20.00%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
U.S. federal statutory rate		21.00%	35.00%	35.00%
Percentage of income attributable to wholly-owned operations and investments for which income tax expense and effective tax rate calculated		100.00%
Valuation allowance	$ 0	$ 0	$ 0
Gross unrecognized tax benefits	4,902	4,902	4,225	$ 3,695	$ 3,513
Unrecognized tax benefits that, if recognized, would affect the effective tax rate	3,997	3,997	3,457
Estimated accrued interest and penalties resulting from unrecognized tax benefits	755	755	540
Foreign subsidiaries earnings	93,000	93,000
Provisional net income tax benefit			$ 9,955
Measurement period estimated net income tax benefit		$ 1,819
Total net income tax benefit attributable to passage of the TCJA	11,774
Minimum
Income Taxes [Line Items]
State and other net operating loss carry forwards expiration date		2,019
Maximum
Income Taxes [Line Items]
State and other net operating loss carry forwards expiration date		2,038
State and other
Income Taxes [Line Items]
Net operating loss carry forwards	8,263	$ 8,263
Federal
Income Taxes [Line Items]
Net operating loss carry forwards	$ 0	$ 0

Components of Income Tax Expens

Components of Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Components Of Income Tax Expense Benefit [Line Items]
U.S. Federal	$ 54,345	$ 69,079	$ 86,719
State	11,631	10,643	9,801
Foreign	6,837	10,499	9,416
Income tax expense	72,813	90,221	105,936
Current	64,523	100,956	103,216
Deferred	8,290	(10,735)	2,720
Income tax expense	$ 72,813	$ 90,221	$ 105,936

Reconciliation of Effective Inc

Reconciliation of Effective Income Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Effective Income Tax Rate [Line Items]
U.S. federal statutory rate	21.00%	35.00%	35.00%
State income taxes, net of federal benefit and other	3.60%	2.40%	2.30%
Excess tax benefits from share-based compensation	(2.00%)	(2.70%)	(1.00%)
Tax effects on foreign income	0.50%	(1.00%)	(0.10%)
GILTI	0.30%
Tax credits and other		(0.60%)	(0.20%)
Repatriation transition tax	(0.90%)	3.00%
Deferred tax impact of enacted tax rate changes	0.30%	(6.30%)
Effective income tax rate attributable to Watsco, Inc.	22.80%	29.80%	36.00%
Taxes attributable to non-controlling interest	(3.10%)	(3.80%)	(5.00%)
Effective income tax rate	19.70%	26.00%	31.00%

Significant Components of Net D

Significant Components of Net Deferred Tax Liabilities (Detail) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017
Components of Net Deferred Tax Liabilities [Line Items]
Share-based compensation		$ 21,517	$ 18,977
Capitalized inventory costs and inventory reserves		2,151	2,107
Allowance for doubtful accounts		1,057	929
Self-insurance reserves		206	153
Other		2,486	2,423
Net operating loss carryforwards		484	291
Total deferred tax assets, gross		27,901	24,880
Valuation allowance		0	0
Total deferred tax assets		27,901	24,880
Deductible goodwill		(69,600)	(67,246)
Depreciation		(10,695)	(5,519)
Other		(8,516)	(5,189)
Total deferred tax liabilities		(88,811)	(77,954)
Net deferred tax liabilities	[1]	$ (60,910)	$ (53,074)
[1]	Net deferred tax liabilities have been included in the consolidated balance sheets in deferred income taxes and other liabilities.

Changes in Gross Unrecognized T

Changes in Gross Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Contingency [Line Items]
Beginning balance	$ 4,225	$ 3,695	$ 3,513
Additions based on tax positions related to the current year	960	801	547
Reductions due to lapse of applicable statute of limitations and tax assessments	(283)	(271)	(365)
Ending balance	$ 4,902	$ 4,225	$ 3,695

Share-Based Compensation and _3

Share-Based Compensation and Benefit Plans - Additional Information (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)Age$ / sharesshares	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options of common stock outstanding | shares	504,617	398,833
Shares withheld as payment for tax withholdings related to share based compensation, market value	$ 3,782	$ 4,674	$ 3,975
Total intrinsic value of stock options exercised	3,500	2,296	4,123
Cash received from Common stock issued	5,006	3,855	4,447
Common stock contribution to 401(k) plan	$ 2,945	$ 2,428	$ 2,348
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate shares of common stock that may be granted | shares	1,500,000
Shares reserved for future grant | shares	477,256
Number of days of service required for an employee to purchase shares	90 days
Discount to employees to purchase shares	5.00%
Shares purchased under ESPP | shares	5,151	5,571	5,956
Average price of the shares purchased by employees | $ / shares	$ 168.21	$ 144.58	$ 125.84
Additional shares issued resulting from cash dividends reinvested in common stock | shares	4,338	3,844	3,442
Net proceeds from shares purchased under ESPP	$ 1,585	$ 1,389	$ 1,206
2014 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of market price that share-based compensation awards are granted at	100.00%
Aggregate shares of common stock that may be granted | shares	2,000,000
Shares of common stock remaining under the 2001 Plan available for issuance under the 2014 Plan | shares	45,421
Shares reserved for future grant | shares	817,782
Contractual term of stock option awards	5 years
2014 Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Years in which options plan vest	2 years
2014 Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Years in which options plan vest	4 years
2014 Plan | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares awarded under plan | shares	601,252
2014 Plan | Class B Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares awarded under plan | shares	626,387
401(k) Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock contribution to 401(k) Plan, shares | shares	17,318	16,389	20,045
Common stock contribution to 401(k) plan	$ 2,945	$ 2,428	$ 2,348
2001 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate shares of common stock that may be granted | shares	0
Contractual term of stock option awards	5 years
Options of common stock outstanding | shares	1,000
2001 Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Years in which options plan vest	2 years
2001 Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Years in which options plan vest	4 years
Non-Vested Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value of non-vested (restricted) stock | $ / shares	$ 167.06	$ 149.47	$ 130.01
Fair value of non-vested stock that vested	$ 9,637	$ 11,580	$ 10,096
Unrecognized share-based compensation expense	$ 118,124
Vesting period related to shares obligated to issue in connection with incentive compensation agreement	11 years 2 months 12 days
Non-Vested Restricted Stock | Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized share-based compensation expense	$ 56,000
Vesting period related to shares obligated to issue in connection with incentive compensation agreement	10 years
Vesting period related to shares obligated to issue in connection with incentive compensation agreement | shares	45,752
Non-Vested Restricted Stock | Chief Executive Officer | Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized share-based compensation expense	$ 9,000
Vesting period related to shares obligated to issue in connection with incentive compensation agreement	4 years
Age of Chief Executive Officer when non-vested (restricted) stock vests | Age	82
Non-Vested Restricted Stock | Chief Executive Officer | Share-based Compensation Award, Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized share-based compensation expense	$ 42,000
Vesting period related to shares obligated to issue in connection with incentive compensation agreement	8 years
Age of Chief Executive Officer when non-vested (restricted) stock vests | Age	86
Non-Vested Restricted Stock | Chief Executive Officer | Share-based Compensation Award, Tranche Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized share-based compensation expense	$ 5,000
Vesting period related to shares obligated to issue in connection with incentive compensation agreement	10 years
Age of Chief Executive Officer when non-vested (restricted) stock vests | Age	88
Non-Vested Restricted Stock | President
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized share-based compensation expense	$ 13,000
Vesting period related to shares obligated to issue in connection with incentive compensation agreement	25 years
Vesting period related to shares obligated to issue in connection with incentive compensation agreement | shares	23,297
Non-Vested Restricted Stock | President | Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized share-based compensation expense	$ 12,000
Vesting period related to shares obligated to issue in connection with incentive compensation agreement	25 years
Age of president when non vested restricted shares vests | Age	62
Non-Vested Restricted Stock | President | Share-based Compensation Award, Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized share-based compensation expense	$ 1,000
Vesting period related to shares obligated to issue in connection with incentive compensation agreement	27 years
Age of president when non vested restricted shares vests | Age	64
Non-Vested Restricted Stock | Employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Age of employee when non-vested (restricted) stock vests | Age	62
Non-Vested Restricted Stock | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares withheld as payment for tax withholdings related to share based compensation, shares | shares		32,454
Shares withheld as payment for tax withholdings related to share based compensation, market value		$ 4,664
Non-Vested Restricted Stock | Common and Class B Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares withheld as payment for tax withholdings related to share based compensation, shares | shares	21,754		30,413
Shares withheld as payment for tax withholdings related to share based compensation, market value	$ 3,775		$ 3,967
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized share-based compensation expense	$ 3,598
Vesting period related to shares obligated to issue in connection with incentive compensation agreement	1 year 9 months 18 days
Fair value of stock options vested	$ 1,607	$ 754	$ 736
Stock Options | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares withheld as payment for tax withholdings related to share based compensation, shares | shares	7,027	350	348
Shares withheld as payment for tax withholdings related to share based compensation, market value	$ 1,269	$ 53	$ 51

Summary of Stock Option Activit

Summary of Stock Option Activity (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Outstanding beginning balance | shares	398,833
Options, Granted | shares	188,550
Options, Exercised | shares	(54,934)
Options, Forfeited | shares	(26,832)
Options, Expired | shares	(1,000)
Options, Outstanding ending balance | shares	504,617
Options, Exercisable | shares	71,487
Weighted-Average Exercise Price, Outstanding beginning balance | $ / shares	$ 136.44
Weighted-Average Exercise Price, Granted | $ / shares	173.48
Weighted-Average Exercise Price, Exercised | $ / shares	114.09
Weighted-Average Exercise Price, Forfeited | $ / shares	155.83
Weighted-Average Exercise Price, Expired | $ / shares	122.62
Weighted-Average Exercise Price, Outstanding ending balance | $ / shares	151.71
Weighted-Average Exercise Price, Exercisable | $ / shares	$ 135.89
Weighted-Average Remaining Contractual Term (in years), Outstanding	3 years 3 months 22 days
Weighted-Average Remaining Contractual Term (in years), Exercisable	2 years 1 month 17 days
Aggregate Intrinsic Value, Outstanding | $	$ 1,733
Aggregate Intrinsic Value, Exercisable | $	$ 826

Summary of Non-Vested Restricte

Summary of Non-Vested Restricted Stock Activity (Detail) - Non-Vested Restricted Stock - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, Non-vested beginning balance	2,985,239
Shares, Granted	142,865
Shares, Vested	(55,502)
Shares, Forfeited	(10,000)
Shares, Non-vested ending balance	3,062,602	2,985,239
Weighted-Average Grant Date Fair Value, Non-vested beginning balance	$ 51.22
Weighted-Average Grant Date Fair Value, Granted	167.06	$ 149.47	$ 130.01
Weighted-Average Grant Date Fair Value, Vested	66.52
Weighted-Average Grant Date Fair Value, Forfeited	142.52
Weighted-Average Grant Date Fair Value, Non-vested ending balance	$ 48.72	$ 51.22

Weighted-Average Assumptions Us

Weighted-Average Assumptions Used for Stock Options Granted (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term in years	4 years 3 months	4 years 3 months	4 years 3 months
Risk-free interest rate	2.69%	1.77%	1.24%
Expected volatility	17.11%	17.41%	18.65%
Expected dividend yield	3.13%	2.82%	2.54%
Grant date fair value	$ 20.05	$ 17.23	$ 16.37

Share-Based Compensation Expens

Share-Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 15,508	$ 13,293	$ 12,319
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	2,014	1,451	1,149
Non-Vested Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 13,494	$ 11,842	$ 11,170

Purchase of Additional Owners_2

Purchase of Additional Ownership Interest in Joint Ventures - Additional Information (Detail) - Carrier Enterprise II - USD ($) $ in Thousands	Feb. 13, 2017	Nov. 29, 2016	Jul. 31, 2011
Business Acquisition [Line Items]
Additional ownership interest acquired	10.00%	10.00%
Cash consideration	$ 42,688	$ 42,909
Controlling interest, ownership percentage	80.00%		60.00%

Investment in Unconsolidated _2

Investment in Unconsolidated Entity - Additional Information (Detail) $ in Thousands	Jul. 05, 2018USD ($)	Jun. 21, 2017USD ($)Locationboard-member	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Jun. 29, 2018
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated entity			$ 3,760	$ 63,600
Proceeds from non-controlling interest for investment in unconsolidated entity			$ 752	$ 12,720
Carrier Enterprise I
Schedule of Equity Method Investments [Line Items]
Ownership percentage by parent		80.00%
Ownership percentage, by non-controlling owners		20.00%
Russell Sigler Inc
Schedule of Equity Method Investments [Line Items]
Ownership interest acquired		34.90%	36.30%
Investment in unconsolidated entity	$ 3,760	$ 63,600
Contribution to investment in unconsolidated entity by controlling interest	3,008	50,880
Proceeds from non-controlling interest for investment in unconsolidated entity	$ 752	$ 12,720
Ownership percentage needed for right to purchase up to 100%		85.00%
Total number of board members | board-member		6
Number of board members that can be appointed based on ownership | board-member		2
Equity method investment, additional ownership interest acquired					1.40%
Russell Sigler Inc | Western United States
Schedule of Equity Method Investments [Line Items]
Number of locations | Location		30
Russell Sigler sales			$ 770,000

Acquisition - Additional Inform

Acquisition - Additional Information (Detail) - USD ($) $ in Thousands	Aug. 23, 2018	Dec. 31, 2018
Business Acquisition [Line Items]
Business acquisition, fair value of common stock		$ 6,846
Alert Labs Inc
Business Acquisition [Line Items]
Business acquisition, cash consideration	$ 5,889
Business acquisition, fair value of common stock	3,991
Adjustment related to previously held equity interest	171
Contingent consideration	$ 3,026
Contingent consideration performance measurement period	3 years
Intangibles and goodwill acquired	$ 14,941
Fair value of intangible assets	1,640
Alert Labs Inc | Patented And Unpatented Technology [Member]
Business Acquisition [Line Items]
Fair value of intangible assets	1,600
Alert Labs Inc | Customer Relationships [Member]
Business Acquisition [Line Items]
Fair value of intangible assets	$ 40
Stock consideration [Member] | Alert Labs Inc
Business Acquisition [Line Items]
Business acquisition, issuance of shares of common stock	23,873
Contingent consideration [Member] | Alert Labs Inc
Business Acquisition [Line Items]
Common stock shares issued	23,230

Changes in Carrying Amount of G

Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 382,729	$ 379,737
Acquired goodwill	13,301
Foreign currency translation adjustment	(4,032)	2,992
Goodwill, Ending Balance	$ 391,998	$ 382,729

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill And Intangible Assets [Line Items]
Amortization expense related to finite lived intangible assets	$ 5,348	$ 5,263	$ 5,213

Intangible Assets (Detail)

Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Intangible Assets [Line Items]
Indefinite lived intangible assets - Trade names, trademarks and distribution rights	$ 119,188	$ 125,194
Finite lived intangible assets:
Accumulated amortization	(43,680)	(38,332)
Finite lived intangible assets, net	28,663	35,871
Intangible assets, net	147,851	161,065
Customer Relationships
Finite lived intangible assets:
Finite lived intangible assets	$ 69,593	73,053
Customer Relationships | Minimum
Intangible Assets [Line Items]
Finite lived intangible assets, Estimated Useful lives, years	10 years
Customer Relationships | Maximum
Intangible Assets [Line Items]
Finite lived intangible assets, Estimated Useful lives, years	15 years
Trade Name
Intangible Assets [Line Items]
Finite lived intangible assets, Estimated Useful lives, years	10 years
Finite lived intangible assets:
Finite lived intangible assets	$ 1,150	$ 1,150
Patented And Unpatented Technology [Member]
Intangible Assets [Line Items]
Finite lived intangible assets, Estimated Useful lives, years	7 years
Finite lived intangible assets:
Finite lived intangible assets	$ 1,600

Amortization Expense Related to

Amortization Expense Related to Finite Lived Intangible Assets (Detail) $ in Thousands	Dec. 31, 2018USD ($)
2,019	$ 5,000
2,020	5,000
2,021	4,200
2,022	3,400
2,023	$ 2,800

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Aug. 23, 2017	Sep. 30, 1999
Stockholders Equity Note [Line Items]
Preferred stock outstanding	0	0
Maximum aggregate offering price under sales agreement				$ 250,000,000
Net proceeds from the sale of Common stock		$ 247,744,000
Direct stock issuance costs		$ 311,000
Number of shares authorized to be repurchased					7,500,000
Treasury stock, shares repurchased	0	0	0
Cost of repurchased shares	$ 114,425,000	$ 114,425,000
Remaining number of shares authorized to be repurchased	1,129,087
Common Stock
Stockholders Equity Note [Line Items]
Sale of common stock, shares		1,498,662
Common Stock
Stockholders Equity Note [Line Items]
Amount of votes common stock is entitled		One
Percentage of Board entitled to elect		25.00%
Treasury stock, shares	4,823,988	4,823,988
Class B Common Stock
Stockholders Equity Note [Line Items]
Amount of votes common stock is entitled		Ten
Treasury stock, shares	48,263	48,263

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Financial Instrument [Line Items]
Estimated fair value of contingent liability	$ 0
Standby Letters of Credit
Financial Instrument [Line Items]
Fair value of contingent liability	1,222,000	$ 2,430,000
Performance Bonds
Financial Instrument [Line Items]
Fair value of contingent liability	$ 3,600,000	$ 4,000,000

Derivatives - Additional Inform

Derivatives - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Foreign Currency Forward Contracts | Cash Flow Hedge
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional value of derivatives	$ 40,000,000
Contract maturity period	One year or less
Contract expiring terms	2019-09
Maximum length of time hedged in cash flow hedge	12 months
Pre-tax loss to be reclassified into earnings within the next 12 months	$ 1,450,000
Foreign Exchange Forward And Option Contracts [Member] | Not Designated as Hedging Instrument, Economic Hedge [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional value of derivatives	$ 6,800,000
Contract expiring terms	2019-02
(Loss) gain from foreign currency forward and option contracts not designated as hedging instruments	$ 129,000	$ (829,000)	$ (306,000)

Impact from Foreign Exchange De

Impact from Foreign Exchange Derivative Instruments Designated as Cash Flow Hedges (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recorded in accumulated other comprehensive loss	$ 2,627	$ (961)	$ (1,321)
Foreign Currency Forward Contracts | Cash Flow Hedge
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recorded in accumulated other comprehensive loss	2,627	(961)
(Gain) loss reclassified from accumulated other comprehensive loss into earnings	$ (215)	$ (491)

Fair Value of Derivative Instru

Fair Value of Derivative Instruments and Location in the Balance Sheets (Detail) - Foreign Exchange Forward And Option Contracts [Member] - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative instruments, assets derivatives	$ 1,320	$ 250
Derivative instruments, liabilities derivatives	14	957
Derivatives Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Derivative instruments, assets derivatives	1,262	70
Derivative instruments, liabilities derivatives	3	773
Not Designated as Hedging Instrument, Economic Hedge [Member]
Derivatives, Fair Value [Line Items]
Derivative instruments, assets derivatives	58	180
Derivative instruments, liabilities derivatives	$ 11	$ 184

Assets and Liabilities Carried

Assets and Liabilities Carried at Fair Value Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Other assets
Assets:
Equity securities	$ 279	$ 332
Other Current Assets
Assets:
Derivative financial instruments	1,320	250
Accrued expenses and other current liabilities
Liabilities:
Derivative financial instruments	14	957
Fair Value Measurements, Level 1 | Other assets
Assets:
Equity securities	279	332
Fair Value Measurements, Level 2 | Other Current Assets
Assets:
Derivative financial instruments	1,320	250
Fair Value Measurements, Level 2 | Accrued expenses and other current liabilities
Liabilities:
Derivative financial instruments	$ 14	$ 957

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Line Items]
Self-insurance reserves	$ 2,311	$ 2,344
Maximum exposure to loss related to involvement with variable interest entity	$ 3,900
Operating leases maximum maturity date	2,028
Rental expense	$ 84,537	$ 84,076	$ 83,260
Non-cancelable purchase obligations for goods	35,000
Carrier and Its Affiliates [Member]
Commitments and Contingencies Disclosure [Line Items]
Non-cancelable purchase obligations for goods	$ 22,000

Future Minimum Leases Payments

Future Minimum Leases Payments under Non-Cancelable Operating Leases (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Operating Leases Future Minimum Payments Due [Line Items]
2,019	$ 70,388
2,020	55,102
2,021	41,321
2,022	28,482
2,023	15,712
Thereafter	8,245
Total minimum payments	$ 219,250

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplier Concentration Risk | Cost of Goods, Total
Related Party Transaction [Line Items]
Percentage of purchases from key suppliers	84.00%	84.00%	85.00%
Moss & Associates LLC | Customary Payments for Remodeling of Corporate Headquarters
Related Party Transaction [Line Items]
Payment for related party transaction	$ 124	$ 951	$ 291
Amount payable to related party	0
Greenberg Traurig, P.A. | Customary Fees for Legal Services
Related Party Transaction [Line Items]
Payment for related party transaction	131	475
Amount payable to related party	0
Carrier and Its Affiliates | Supplier Concentration Risk
Related Party Transaction [Line Items]
Amount payable to Carrier and its affiliates, net of receivables	71,000	75,000
Revenues from sales to Carrier and its affiliates	$ 84,000	$ 64,000	$ 56,000
Carrier and Its Affiliates | Supplier Concentration Risk | Cost of Goods, Total
Related Party Transaction [Line Items]
Percentage of purchases from key suppliers	62.00%	62.00%	62.00%

Revenues and Long-Lived Assets

Revenues and Long-Lived Assets by Geographical Area (Detail) - USD ($) $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2018		Sep. 30, 2018	[1]	Jun. 30, 2018	[1]	Mar. 31, 2018	[1]	Dec. 31, 2017		Sep. 30, 2017	[1]	Jun. 30, 2017	[1]	Mar. 31, 2017	[1]	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Geographic Area Information [Line Items]
Revenues	$ 991,326	[1]	$ 1,296,007		$ 1,332,743		$ 926,577		$ 964,345	[1]	$ 1,229,591		$ 1,275,924		$ 872,095		$ 4,546,653	$ 4,341,955	$ 4,220,702
Long-Lived Assets	719,227								709,480								719,227	709,480
United States
Geographic Area Information [Line Items]
Revenues																	4,126,639	3,919,684	3,813,204
Long-Lived Assets	550,939								540,136								550,939	540,136
Canada
Geographic Area Information [Line Items]
Revenues																	291,685	269,603	267,220
Long-Lived Assets	162,648								163,944								162,648	163,944
Mexico
Geographic Area Information [Line Items]
Revenues																	128,329	152,668	$ 140,278
Long-Lived Assets	$ 5,640								$ 5,400								$ 5,640	$ 5,400
[1]	Sales of residential central air conditioners, heating equipment and parts and supplies are seasonal. Demand related to the residential central air conditioning replacement market is typically highest in the second and third quarters, and demand for heating equipment is usually highest in the fourth quarter. Demand related to the new construction sectors throughout most of the markets is fairly evenly distributed throughout the year except for dependence on housing completions and related weather and economic conditions.

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash Flow Supplemental Disclosures [Line Items]
Interest paid	$ 3,065	$ 5,773	$ 3,362
Income taxes net of refunds	115,301	$ 48,056	$ 99,006
Common stock issued for Alert Labs Inc.	$ 6,846

Selected Quarterly Financial _3

Selected Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2018		Sep. 30, 2018		Jun. 30, 2018		Mar. 31, 2018		Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Quarterly Financial Data [Line Items]
Revenues	$ 991,326	[1]	$ 1,296,007	[1]	$ 1,332,743	[1]	$ 926,577	[1]	$ 964,345	[1]	$ 1,229,591	[1]	$ 1,275,924	[1]	$ 872,095	[1]	$ 4,546,653		$ 4,341,955		$ 4,220,702
Gross profit	249,644		319,009		320,766		230,833		240,930		295,895		310,278		218,556		1,120,252		1,065,659		1,034,584
Net income attributable to Watsco, Inc.	$ 39,593		$ 79,163		$ 89,957		$ 34,219		$ 43,255		$ 65,029		$ 73,756		$ 26,181		$ 242,932		$ 208,221		$ 182,810
Earnings per share for Common and Class B common stock:
Basic	$ 1.02	[2]	$ 2.12	[2]	$ 2.41	[2]	$ 0.89	[2]	$ 1.19	[2]	$ 1.82	[2]	$ 2.07	[2]	$ 0.71	[2]	$ 6.50	[2]	$ 5.81	[2]	$ 5.16
Diluted	$ 1.02	[2]	$ 2.11	[2]	$ 2.40	[2]	$ 0.89	[2]	$ 1.19	[2]	$ 1.82	[2]	$ 2.07	[2]	$ 0.71	[2]	$ 6.49	[2]	$ 5.81	[2]	$ 5.15
[1]	Sales of residential central air conditioners, heating equipment and parts and supplies are seasonal. Demand related to the residential central air conditioning replacement market is typically highest in the second and third quarters, and demand for heating equipment is usually highest in the fourth quarter. Demand related to the new construction sectors throughout most of the markets is fairly evenly distributed throughout the year except for dependence on housing completions and related weather and economic conditions.
[2]	Quarterly and year-to-date earnings per share are calculated on an individual basis; therefore, the sum of earnings per share amounts for the quarters may not equal earnings per share amounts for the year.