Fastenal (FAST) 10-Q 16 Oct 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 09, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Trading Symbol	fast
Entity Registrant Name	FASTENAL CO
Entity Central Index Key	815,556
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		287,056,618

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 129.7	$ 116.9
Trade accounts receivable, net of allowance for doubtful accounts of $11.7 and $11.9, respectively	772.5	607.8
Inventories	1,194.7	1,092.9
Prepaid income taxes	2.2	0
Other current assets	126.4	118.1
Total current assets	2,225.5	1,935.7
Property and equipment, net	883.8	893.6
Other assets	84.6	81.2
Total assets	3,193.9	2,910.5
Current liabilities:
Current portion of debt	2.5	3
Accounts payable	186	147.5
Accrued expenses	227.6	194
Income taxes payable	0	6.5
Total current liabilities	416.1	351
Long-term debt	387.5	412
Deferred income taxes	74.7	50.6
Stockholders' equity:
Preferred stock: $0.01 par value, 5,000,000 shares authorized, no shares issued or outstanding	0	0
Common stock: $0.01 par value, 400,000,000 shares authorized, 287,056,618 and 287,591,536 shares issued and outstanding, respectively	2.9	2.9
Additional paid-in capital	7.4	8.5
Retained earnings	2,342	2,110.6
Accumulated other comprehensive loss	(36.7)	(25.1)
Total stockholders' equity	2,315.6	2,096.9
Total liabilities and stockholders' equity	$ 3,193.9	$ 2,910.5

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Trade accounts receivable, allowance for doubtful accounts	$ 11.7	$ 11.9
Preferred stock
Par value (in dollars per share)	$ 0.01	$ 0.01
Authorized (in shares)	5,000,000	5,000,000
Issued (in shares)	0	0
Outstanding (in shares)	0	0
Common stock
Par value (in dollars per share)	$ 0.01	$ 0.01
Authorized (in shares)	400,000,000	400,000,000
Issued (in shares)	287,056,618	287,591,536
Outstanding (in shares)	287,056,618	287,591,536

Condensed Consolidated Statemen

Condensed Consolidated Statements of Earnings - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Net sales	$ 1,279.8	$ 1,132.8	$ 3,733.5	$ 3,302
Cost of sales	664	576.9	1,922.4	1,669.6
Gross profit	615.8	555.9	1,811.1	1,632.4
Operating and administrative expenses	353.8	327.5	1,045.8	955
Gain on sale of property and equipment	(0.3)	(0.1)	(0.5)	(1.1)
Operating income	262.3	228.5	765.8	678.5
Interest income	0.1	0.1	0.3	0.3
Interest expense	(3)	(2.6)	(8.9)	(6.5)
Earnings before income taxes	259.4	226	757.2	672.3
Income tax expense	61.8	82.9	174.1	246.1
Net earnings	$ 197.6	$ 143.1	$ 583.1	$ 426.2
Basic net earnings per share (in dollars per share)	$ 0.69	$ 0.50	$ 2.03	$ 1.48
Diluted net earnings per share (in dollars per share)	$ 0.69	$ 0.50	$ 2.03	$ 1.48
Basic weighted average shares outstanding (in shares)	287,006,910	287,456,943	287,263,379	288,451,470
Diluted weighted average shares outstanding (in shares)	287,263,222	287,578,043	287,458,408	288,591,574

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net earnings	$ 197.6	$ 143.1	$ 583.1	$ 426.2
Other comprehensive income, net of tax:
Foreign currency translation adjustments (net of tax of $0.0 in 2018 and 2017)	(0.8)	8.2	(11.6)	19.2
Comprehensive income	$ 196.8	$ 151.3	$ 571.5	$ 445.4

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustments, tax	$ 0	$ 0	$ 0	$ 0

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net earnings	$ 583.1	$ 426.2
Adjustments to reconcile net earnings to net cash provided by operating activities, net of acquisitions:
Depreciation of property and equipment	99.3	92.3
Gain on sale of property and equipment	(0.5)	(1.1)
Bad debt expense	5.1	6.2
Deferred income taxes	24.1	2.3
Stock-based compensation	3.8	4
Amortization of intangible assets	3	2.8
Changes in operating assets and liabilities, net of acquisitions:
Trade accounts receivable	(172)	(126.2)
Inventories	(104.9)	(31.2)
Other current assets	(8.3)	(15.2)
Accounts payable	38.5	35.9
Accrued expenses	33.6	42.3
Income taxes	(8.7)	19.5
Other	0.1	(1.9)
Net cash provided by operating activities	496.2	455.9
Cash flows from investing activities:
Purchases of property and equipment	(97.1)	(82.7)
Proceeds from sale of property and equipment	8.3	6.2
Cash paid for acquisitions	(3.7)	(58.7)
Other	(6.4)	(3)
Net cash used in investing activities	(98.9)	(138.2)
Cash flows from financing activities:
Proceeds from debt obligations	640	805
Payments against debt obligations	(665)	(750)
Proceeds from exercise of stock options	11.3	3.5
Purchases of common stock	(40.4)	(82.6)
Payments of dividends	(327.5)	(277.1)
Net cash used in financing activities	(381.6)	(301.2)
Effect of exchange rate changes on cash and cash equivalents	(2.9)	4.2
Net increase in cash and cash equivalents	12.8	20.7
Cash and cash equivalents at beginning of period	116.9	112.7
Cash and cash equivalents at end of period	129.7	133.4
Supplemental disclosure of cash flow information:
Cash paid for interest	8.9	6.1
Net cash paid for income taxes	$ 158	$ 223.8

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	(1) Basis of Presentation The accompanying unaudited condensed consolidated financial statements of Fastenal Company and subsidiaries (collectively referred to as the company, Fastenal, or by terms such as we, our, or us) have been prepared in accordance with U.S. generally accepted accounting principles ('GAAP') for interim financial information. They do not include all information and footnotes required by U.S. GAAP for complete financial statements. However, except as described herein, there has been no material change in the information disclosed in the Notes to Consolidated Financial Statements included in our consolidated financial statements as of and for the year ended December 31, 2017 . In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. Recently Adopted Accounting Pronouncements Effective January 1, 2018, we adopted the Financial Accounting Standards Board ('FASB') Accounting Standards Update ('ASU') 2014-09, Revenue from Contracts with Customers (Topic 606) , and ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of Effective Date, which deferred the effective date of ASU 2014-09 by one year. ASU 2014-09 supersedes the revenue recognition requirements in ASC 605, Revenue Recognition, and is based on the principle that revenue is recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. It also requires additional disclosure about the nature, amount, timing, and uncertainty of revenue, cash flows arising from customer contracts, including significant judgments and changes in judgments, and assets recognized from costs incurred to obtain or fulfill a contract. The adoption of ASU 2014-09, using the modified retrospective approach, had no significant impact on our results of operations, cash flows, or financial position. Revenue continues to be recognized at a point in time for our product sales when products are delivered to or picked up by the customer and revenue for shipping and handling charges continues to be recognized when products are delivered to or picked up by the customer. We continue to reduce revenue for estimates of sales incentives based on probability estimates and for product returns based on historical return rates. Additional information and disclosures required by this new standard are contained in Note 2, 'Revenue' . In March 2018, we adopted FASB ASU 2018-05, Income Taxes (Topic 740): Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118 , which updates the income tax accounting in U.S. GAAP to reflect the Securities and Exchange Commission ('SEC') interpretive guidance released on December 22, 2017, when the Tax Cuts and Jobs Act (the 'Tax Act') was signed into law. Additional information regarding the adoption of this standard is contained in Note 4, 'Income Taxes' . Recently Issued Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02, Leases , which introduces the recognition of lease assets and lease liabilities by lessees for those leases classified as operating leases under previous guidance. The update is effective for annual reporting periods beginning after December 15, 2018, including interim periods within those reporting periods, with early adoption permitted. The original guidance required application on a modified retrospective basis with the earliest period presented. In August 2018, the FASB issued ASU 2018-11, Targeted Improvements to ASC 842 , which includes an option to not restate comparative periods in transition and elect to use the effective date of ASC 842, Leases , as the date of initial application of transition. Based on the effective date, this guidance will apply and we will adopt this ASU beginning on January 1, 2019 and plan to elect the transition option provided under ASU 2018-11. While we are still in the process of evaluating the effect of adoption on our consolidated financial statements and are currently assessing our leases, we expect the adoption will result in a material increase in the assets and liabilities recorded on our Condensed Consolidated Balance Sheets and additional qualitative and quantitative disclosures.

Revenue

Revenue	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue	(2) Revenue Revenue Recognition Net sales include products and shipping and handling charges, net of estimates for product returns and any related sales incentives. Revenue is measured as the amount of consideration we expect to receive in exchange for transferring products. All revenue is recognized when we satisfy our performance obligations under the contract. We recognize revenue by transferring the promised products to the customer, with the majority of revenue recognized at the point in time the customer obtains control of the products. We recognize revenue for shipping and handling charges at the time the products are delivered to or picked up by the customer. We estimate product returns based on historical return rates. Using probability assessments, we estimate sales incentives expected to be paid over the term of the contract. The majority of our contracts have a single performance obligation and are short term in nature. Sales taxes and value added taxes in foreign jurisdictions that are collected from customers and remitted to governmental authorities are accounted for on a net basis and therefore are excluded from net sales. Accounts Receivable Credit is extended based upon an evaluation of the customer's financial condition. Accounts receivable are stated at their estimated net realizable value. The allowance for doubtful accounts is based on an analysis of customer accounts and our historical experience with accounts receivable write-offs. Disaggregation of Revenue Our revenues related to the following geographic areas were as follows for the periods ended September 30 : Nine-month Period Three-month Period 2018 2017 2018 2017 United States $ 3,226.0 2,897.4 $ 1,104.9 989.0 Canada 228.4 190.3 76.6 67.0 Other foreign countries 279.1 214.3 98.3 76.8 Total revenues $ 3,733.5 3,302.0 $ 1,279.8 1,132.8 The percentages of our sales by end market were as follows for the periods ended September 30 : Nine-month Period Three-month Period 2018 2017 2018 2017 Manufacturing 66.7 % 66.5 % 66.4 % 66.5 % Non-Residential construction 13.1 % 13.0 % 13.4 % 13.0 % Other 20.2 % 20.5 % 20.2 % 20.5 % 100.0 % 100.0 % 100.0 % 100.0 % The percentages of our sales by product line were as follows for the periods ended September 30 (1) : Nine-month Period Three-month Period Type Introduced 2018 2017 2018 2017 Fasteners (2) 1967 35.1 % 35.8 % 34.7 % 35.6 % Tools 1993 10.1 % 10.1 % 10.1 % 10.3 % Cutting tools 1996 5.7 % 5.8 % 5.7 % 5.8 % Hydraulics & pneumatics 1996 6.9 % 6.8 % 6.7 % 6.7 % Material handling 1996 5.8 % 6.0 % 5.7 % 5.8 % Janitorial supplies 1996 7.6 % 7.3 % 7.8 % 7.4 % Electrical supplies 1997 4.6 % 4.9 % 4.6 % 4.8 % Welding supplies 1997 4.1 % 4.2 % 4.1 % 4.2 % Safety supplies (3) 1999 17.0 % 16.1 % 17.3 % 16.4 % Other 3.1 % 3.0 % 3.3 % 3.0 % 100.0 % 100.0 % 100.0 % 100.0 % (1) In 2018, we reclassified certain product category designations and have conformed the prior period percentages to the current year presentation. (2) Fastener product line represents fasteners and miscellaneous supplies. (3) The safety supplies product line has expanded as a percentage of sales in the last several years due to our industrial vending program.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2018
Stockholders' Equity Note [Abstract]
Stockholders' Equity	(3) Stockholders' Equity Dividends On October 9, 2018 , our board of directors declared a dividend of $0.40 per share of common stock to be paid in cash on November 21, 2018 to shareholders of record at the close of business on October 24, 2018 . Since 2011, we have paid quarterly dividends. Our board of directors intends to continue paying quarterly dividends, provided that any future determination as to payment of dividends will depend on the financial condition and results of operations of the company and such other factors as are deemed relevant by the board of directors. The following table presents the dividends either paid previously or declared by our board of directors for future payment on a per share basis: 2018 2017 First quarter $ 0.37 0.32 Second quarter 0.37 0.32 Third quarter 0.40 0.32 Fourth quarter 0.40 0.32 Total $ 1.54 1.28 Stock Options The following tables summarize the details of options granted under our stock option plan that were still outstanding as of September 30, 2018 , and the assumptions used to value these grants. All such grants were effective at the close of business on the date of grant. Options Granted Option Exercise (Strike) Price Closing Stock Price on Date of Grant September 30, 2018 Date of Grant Options Outstanding Options Exercisable January 2, 2018 541,786 $ 55.00 $ 54.54 525,525 21,185 January 3, 2017 764,789 $ 47.00 $ 46.95 683,528 — April 19, 2016 845,440 $ 46.00 $ 45.74 706,116 — April 21, 2015 893,220 $ 42.00 $ 41.26 630,784 130,318 April 22, 2014 955,000 $ 56.00 $ 50.53 519,750 314,000 April 16, 2013 205,000 $ 54.00 $ 49.25 91,249 57,506 April 17, 2012 1,235,000 $ 54.00 $ 49.01 828,750 716,250 April 19, 2011 410,000 $ 35.00 $ 31.78 52,850 40,350 April 20, 2010 530,000 $ 30.00 $ 27.13 33,150 33,150 Total 6,380,235 4,071,702 1,312,759 Date of Grant Risk-free Interest Rate Expected Life of Option in Years Expected Dividend Yield Expected Stock Volatility Estimated Fair Value of Stock Option January 2, 2018 2.2 % 5.00 2.3 % 23.45 % $ 10.03 January 3, 2017 1.9 % 5.00 2.6 % 24.49 % $ 8.40 April 19, 2016 1.3 % 5.00 2.6 % 26.34 % $ 8.18 April 21, 2015 1.3 % 5.00 2.7 % 26.84 % $ 7.35 April 22, 2014 1.8 % 5.00 2.0 % 28.55 % $ 9.57 April 16, 2013 0.7 % 5.00 1.6 % 37.42 % $ 12.66 April 17, 2012 0.9 % 5.00 1.4 % 39.25 % $ 13.69 April 19, 2011 2.1 % 5.00 1.6 % 39.33 % $ 11.20 April 20, 2010 2.6 % 5.00 1.5 % 39.10 % $ 8.14 All of the options in the tables above vest and become exercisable over a period of up to eight years . Generally, each option will terminate approximately nine years after the grant date. The fair value of each share-based option is estimated on the date of grant using a Black-Scholes valuation method that uses the assumptions listed above. The risk-free interest rate is based on the U.S. Treasury rate over the expected life of the option at the time of grant. The expected life is the average length of time over which we expect the employee groups will exercise their options, which is based on historical experience with similar grants. The dividend yield is estimated over the expected life of the option based on our current dividend payout, historical dividends paid, and expected future cash dividends. Expected stock volatilities are based on the movement of our stock price over the most recent historical period equivalent to the expected life of the option. Compensation expense equal to the grant date fair value is recognized for all of these awards over the vesting period. The stock-based compensation expense for the nine -month periods ended September 30, 2018 and 2017 was $3.8 and $4.0 , respectively. Unrecognized stock-based compensation expense related to outstanding unvested stock options as of September 30, 2018 was $14.9 and is expected to be recognized over a weighted average period of 4.07 years . Any future changes in estimated forfeitures will impact this amount. Earnings Per Share The following tables present a reconciliation of the denominators used in the computation of basic and diluted earnings per share and a summary of the options to purchase shares of common stock which were excluded from the diluted earnings per share calculation because they were anti-dilutive: Nine-month Period Three-month Period Reconciliation 2018 2017 2018 2017 Basic weighted average shares outstanding 287,263,379 288,451,470 287,006,910 287,456,943 Weighted shares assumed upon exercise of stock options 195,029 140,104 256,312 121,100 Diluted weighted average shares outstanding 287,458,408 288,591,574 287,263,222 287,578,043 Nine-month Period Three-month Period Summary of Anti-dilutive Options Excluded 2018 2017 2018 2017 Options to purchase shares of common stock 1,597,342 3,881,605 1,534,795 3,848,126 Weighted average exercise price of options $ 55.02 49.21 $ 55.02 49.18 Any dilutive impact summarized above related to periods when the average market price of our stock exceeded the exercise price of the potentially dilutive stock options then outstanding.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	(4) Income Taxes Fastenal files income tax returns in the United States federal jurisdiction, all states, and various local and foreign jurisdictions. With limited exceptions, we are no longer subject to income tax examinations by taxing authorities for taxable years before 2015 in the case of United States federal examinations, and 2013 in the case of foreign, state, and local examinations. During the first nine months of 2018, there were no material changes in unrecognized tax benefits. On December 22, 2017, the Tax Act was signed into law. The Tax Act made broad and complex changes to the U.S. tax code which include: a lowering of the U.S. federal corporate income tax rate from 35% to 21% effective January 1, 2018, accelerated expensing of qualified capital investments for a specific period, and a transition from a worldwide to a territorial tax system which will require companies to pay a one-time transition tax on certain unrepatriated earnings from foreign subsidiaries. ASC 740, Income Taxes, requires a company to record the effects of a tax law change in the period of enactment. ASU 2018-05 allows a company to record a provisional amount when it does not have the necessary information available, prepared, or analyzed in reasonable detail to complete its accounting for the change in the tax law. The measurement period ends when the company has obtained, prepared, and analyzed the information necessary to finalize its accounting, but cannot extend beyond one year. We recorded income tax expense of $174.1 in the first nine months of 2018, or 23.0% of earnings before income taxes. This amount reflects primarily two items: (1) The Tax Act resulted in a lower tax rate beginning in the first quarter of 2018. This includes the estimated impacts of requiring a current inclusion in U.S. federal income of certain earnings of controlled foreign corporations, allowing a domestic corporation an immediate deduction in the U.S. taxable income for a portion of its foreign derived intangible income, and the base erosion anti-abuse tax. These estimates had an immaterial impact on our effective income tax rate. (2) During 2018, we recorded discrete income tax items to adjust our estimated transition tax liability and to reflect the estimated impacts of accelerating depreciation for certain physical assets. These discrete items resulted in approximately $10.3 of income tax benefit during the first nine months of 2018. We will continue to monitor and evaluate guidance and clarifications from the Internal Revenue Service ('IRS') as it relates to the Tax Act and will refine these estimates as necessary. In general, it is our practice and intention to permanently reinvest the earnings of our foreign subsidiaries and repatriate earnings only when the tax impact is zero or very minimal and that position has not changed following incurring the transition tax under the Tax Act. No deferred taxes have been provided for withholding taxes or other taxes that would result upon repatriation of our foreign investments to the United States. It is not practicable to estimate the amount of deferred income tax liabilities related to investments in these foreign subsidiaries.

Operating Leases

Operating Leases	9 Months Ended
	Sep. 30, 2018
Leases, Operating [Abstract]
Operating Leases	(5) Operating Leases Certain operating leases for pick-up trucks contain residual value guarantee provisions which would generally become due at the expiration of the operating lease agreement if the fair value of the leased vehicles is less than the guaranteed residual value. The aggregate residual value guarantee related to these leases is approximately $83.0 . We believe the likelihood of funding the guarantee obligation under any provision of the operating lease agreements is remote other than where we have established an accrual for estimated losses, which is immaterial at September 30, 2018 . To the extent our fleet contains vehicles we estimate will settle at a gain, such gains on these vehicles will be recognized when we sell the vehicle.

Debt Commitments

Debt Commitments	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Debt Commitments	(6) Debt Commitments Credit Facility, Notes Payable, and Commitments Debt obligations and letters of credit outstanding at the end of each period consisted of the following: September 30, 2018 December 31, 2017 Outstanding loans under unsecured revolving credit facility $ 255.0 280.0 2.00% Senior unsecured promissory note payable 40.0 40.0 2.45% Senior unsecured promissory note payable 35.0 35.0 3.22% Senior unsecured promissory note payable 60.0 60.0 Total debt 390.0 415.0 Less: Current portion of debt (2.5 ) (3.0 ) Long-term debt $ 387.5 412.0 Outstanding letters of credit under unsecured revolving credit facility - contingent obligation $ 36.3 36.3 Unsecured Revolving Credit Facility We have a $700.0 committed unsecured revolving credit facility ('Credit Facility'). The Credit Facility includes a committed letter of credit subfacility of $55.0 . The commitments under the Credit Facility will expire (and any borrowings outstanding under the Credit Facility will become due and payable) on March 10, 2020 . In the next twelve months, we have the ability and intent to repay a portion of the outstanding loans using cash; therefore, we have classified this portion as a current liability. The Credit Facility contains certain financial and other covenants, and our right to borrow under the Credit Facility is conditioned upon, among other things, our compliance with these covenants. We are currently in compliance with these covenants. Borrowings under the Credit Facility generally bear interest at a rate per annum equal to the London Interbank Offered Rate (' LIBOR ') for interest periods of various lengths selected by us, plus 0.95% . Based on the interest periods we have chosen, our weighted per annum interest rate at September 30, 2018 was approximately 3.2% . We pay a commitment fee for the unused portion of the Credit Facility. This fee is either 0.10% or 0.125% per annum based on our usage of the Credit Facility. Senior Unsecured Promissory Notes Payable On July 20, 2016 (the 'Effective Date'), we entered into a master note agreement (the 'Master Note Agreement') with certain institutional lenders, pursuant to which, during the period commencing on the Effective Date and ending three years thereafter, we may issue at our discretion in private placements, and the institutional lenders may purchase at their discretion, senior unsecured promissory notes of the company (the 'Notes') in the aggregate principal amount outstanding from time to time of up to $200.0 . The Notes will bear interest at either a fixed rate, or a floating rate based on LIBOR for an interest period of one , three , or six months . The Notes will mature no later than 12 years after the date of issuance thereof, in the case of fixed rate Notes, or 10 years after the date of issuance thereof, in the case of floating rate Notes. All of the Notes will be prepayable at our option in whole or in part. The Master Note Agreement contains certain financial and other covenants. We are currently in compliance with these covenants. Three series of Notes are currently outstanding under the Master Note Agreement. The first series of Notes ('Series A'), was issued on the Effective Date, is in an aggregate principal amount of $40.0 , is due and payable in full on July 20, 2021, and bears interest at a fixed rate of 2.00% per annum. The second series of Notes ('Series B'), was issued on the Effective Date, is in an aggregate principal amount of $35.0 , is due and payable in full on July 20, 2022, and bears interest at a fixed rate of 2.45% per annum. The third series of Notes ('Series C'), was issued on March 1, 2017, is in an aggregate principal amount of $60.0 , is due and payable in full on March 1, 2024, and bears interest at a fixed rate of 3.22% per annum. There is no amortization of these Notes prior to their maturity dates. Interest on the Notes is payable quarterly in arrears on January 20, April 20, July 20, and October 20 of each year. The carrying value of the Notes approximates fair value. The fair value was based on available external pricing data and current market rates for similar debt instruments, among other factors, which are classified as a Level 2 measurement under the fair value hierarchy.

Legal Contingencies

Legal Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Legal Contingencies	(7) Legal Contingencies The nature of our potential exposure to legal contingencies is described in our 2017 annual report on Form 10-K in Note 11 of the Notes to Consolidated Financial Statements. As of September 30, 2018 , there were no litigation matters that we consider to be probable or reasonably possible to have a material adverse outcome.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	(8) Subsequent Events We evaluated all subsequent event activity and concluded that no subsequent events have occurred that would require recognition in the condensed consolidated financial statements or disclosure in the Notes to Condensed Consolidated Financial Statements, with the exception of the dividend declaration disclosed in Note 3 'Stockholders' Equity'.

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The accompanying unaudited condensed consolidated financial statements of Fastenal Company and subsidiaries (collectively referred to as the company, Fastenal, or by terms such as we, our, or us) have been prepared in accordance with U.S. generally accepted accounting principles ('GAAP') for interim financial information. They do not include all information and footnotes required by U.S. GAAP for complete financial statements. However, except as described herein, there has been no material change in the information disclosed in the Notes to Consolidated Financial Statements included in our consolidated financial statements as of and for the year ended December 31, 2017 . In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included.
Recently Adopted and Recently Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements Effective January 1, 2018, we adopted the Financial Accounting Standards Board ('FASB') Accounting Standards Update ('ASU') 2014-09, Revenue from Contracts with Customers (Topic 606) , and ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of Effective Date, which deferred the effective date of ASU 2014-09 by one year. ASU 2014-09 supersedes the revenue recognition requirements in ASC 605, Revenue Recognition, and is based on the principle that revenue is recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. It also requires additional disclosure about the nature, amount, timing, and uncertainty of revenue, cash flows arising from customer contracts, including significant judgments and changes in judgments, and assets recognized from costs incurred to obtain or fulfill a contract. The adoption of ASU 2014-09, using the modified retrospective approach, had no significant impact on our results of operations, cash flows, or financial position. Revenue continues to be recognized at a point in time for our product sales when products are delivered to or picked up by the customer and revenue for shipping and handling charges continues to be recognized when products are delivered to or picked up by the customer. We continue to reduce revenue for estimates of sales incentives based on probability estimates and for product returns based on historical return rates. Additional information and disclosures required by this new standard are contained in Note 2, 'Revenue' . In March 2018, we adopted FASB ASU 2018-05, Income Taxes (Topic 740): Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118 , which updates the income tax accounting in U.S. GAAP to reflect the Securities and Exchange Commission ('SEC') interpretive guidance released on December 22, 2017, when the Tax Cuts and Jobs Act (the 'Tax Act') was signed into law. Additional information regarding the adoption of this standard is contained in Note 4, 'Income Taxes' . Recently Issued Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02, Leases , which introduces the recognition of lease assets and lease liabilities by lessees for those leases classified as operating leases under previous guidance. The update is effective for annual reporting periods beginning after December 15, 2018, including interim periods within those reporting periods, with early adoption permitted. The original guidance required application on a modified retrospective basis with the earliest period presented. In August 2018, the FASB issued ASU 2018-11, Targeted Improvements to ASC 842 , which includes an option to not restate comparative periods in transition and elect to use the effective date of ASC 842, Leases , as the date of initial application of transition. Based on the effective date, this guidance will apply and we will adopt this ASU beginning on January 1, 2019 and plan to elect the transition option provided under ASU 2018-11. While we are still in the process of evaluating the effect of adoption on our consolidated financial statements and are currently assessing our leases, we expect the adoption will result in a material increase in the assets and liabilities recorded on our Condensed Consolidated Balance Sheets and additional qualitative and quantitative disclosures.
Revenue Recognition	Net sales include products and shipping and handling charges, net of estimates for product returns and any related sales incentives. Revenue is measured as the amount of consideration we expect to receive in exchange for transferring products. All revenue is recognized when we satisfy our performance obligations under the contract. We recognize revenue by transferring the promised products to the customer, with the majority of revenue recognized at the point in time the customer obtains control of the products. We recognize revenue for shipping and handling charges at the time the products are delivered to or picked up by the customer. We estimate product returns based on historical return rates. Using probability assessments, we estimate sales incentives expected to be paid over the term of the contract. The majority of our contracts have a single performance obligation and are short term in nature. Sales taxes and value added taxes in foreign jurisdictions that are collected from customers and remitted to governmental authorities are accounted for on a net basis and therefore are excluded from net sales.
Accounts Receivable	Credit is extended based upon an evaluation of the customer's financial condition. Accounts receivable are stated at their estimated net realizable value. The allowance for doubtful accounts is based on an analysis of customer accounts and our historical experience with accounts receivable write-offs.

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	Our revenues related to the following geographic areas were as follows for the periods ended September 30 : Nine-month Period Three-month Period 2018 2017 2018 2017 United States $ 3,226.0 2,897.4 $ 1,104.9 989.0 Canada 228.4 190.3 76.6 67.0 Other foreign countries 279.1 214.3 98.3 76.8 Total revenues $ 3,733.5 3,302.0 $ 1,279.8 1,132.8 The percentages of our sales by end market were as follows for the periods ended September 30 : Nine-month Period Three-month Period 2018 2017 2018 2017 Manufacturing 66.7 % 66.5 % 66.4 % 66.5 % Non-Residential construction 13.1 % 13.0 % 13.4 % 13.0 % Other 20.2 % 20.5 % 20.2 % 20.5 % 100.0 % 100.0 % 100.0 % 100.0 % The percentages of our sales by product line were as follows for the periods ended September 30 (1) : Nine-month Period Three-month Period Type Introduced 2018 2017 2018 2017 Fasteners (2) 1967 35.1 % 35.8 % 34.7 % 35.6 % Tools 1993 10.1 % 10.1 % 10.1 % 10.3 % Cutting tools 1996 5.7 % 5.8 % 5.7 % 5.8 % Hydraulics & pneumatics 1996 6.9 % 6.8 % 6.7 % 6.7 % Material handling 1996 5.8 % 6.0 % 5.7 % 5.8 % Janitorial supplies 1996 7.6 % 7.3 % 7.8 % 7.4 % Electrical supplies 1997 4.6 % 4.9 % 4.6 % 4.8 % Welding supplies 1997 4.1 % 4.2 % 4.1 % 4.2 % Safety supplies (3) 1999 17.0 % 16.1 % 17.3 % 16.4 % Other 3.1 % 3.0 % 3.3 % 3.0 % 100.0 % 100.0 % 100.0 % 100.0 % (1) In 2018, we reclassified certain product category designations and have conformed the prior period percentages to the current year presentation. (2) Fastener product line represents fasteners and miscellaneous supplies. (3) The safety supplies product line has expanded as a percentage of sales in the last several years due to our industrial vending program.

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2018
Stockholders' Equity Note [Abstract]
Schedule of Dividends Paid Previously or Declared	The following table presents the dividends either paid previously or declared by our board of directors for future payment on a per share basis: 2018 2017 First quarter $ 0.37 0.32 Second quarter 0.37 0.32 Third quarter 0.40 0.32 Fourth quarter 0.40 0.32 Total $ 1.54 1.28
Stock Options Granted	The following tables summarize the details of options granted under our stock option plan that were still outstanding as of September 30, 2018 , and the assumptions used to value these grants. All such grants were effective at the close of business on the date of grant. Options Granted Option Exercise (Strike) Price Closing Stock Price on Date of Grant September 30, 2018 Date of Grant Options Outstanding Options Exercisable January 2, 2018 541,786 $ 55.00 $ 54.54 525,525 21,185 January 3, 2017 764,789 $ 47.00 $ 46.95 683,528 — April 19, 2016 845,440 $ 46.00 $ 45.74 706,116 — April 21, 2015 893,220 $ 42.00 $ 41.26 630,784 130,318 April 22, 2014 955,000 $ 56.00 $ 50.53 519,750 314,000 April 16, 2013 205,000 $ 54.00 $ 49.25 91,249 57,506 April 17, 2012 1,235,000 $ 54.00 $ 49.01 828,750 716,250 April 19, 2011 410,000 $ 35.00 $ 31.78 52,850 40,350 April 20, 2010 530,000 $ 30.00 $ 27.13 33,150 33,150 Total 6,380,235 4,071,702 1,312,759
Fair Value Assumptions for Options Granted	Date of Grant Risk-free Interest Rate Expected Life of Option in Years Expected Dividend Yield Expected Stock Volatility Estimated Fair Value of Stock Option January 2, 2018 2.2 % 5.00 2.3 % 23.45 % $ 10.03 January 3, 2017 1.9 % 5.00 2.6 % 24.49 % $ 8.40 April 19, 2016 1.3 % 5.00 2.6 % 26.34 % $ 8.18 April 21, 2015 1.3 % 5.00 2.7 % 26.84 % $ 7.35 April 22, 2014 1.8 % 5.00 2.0 % 28.55 % $ 9.57 April 16, 2013 0.7 % 5.00 1.6 % 37.42 % $ 12.66 April 17, 2012 0.9 % 5.00 1.4 % 39.25 % $ 13.69 April 19, 2011 2.1 % 5.00 1.6 % 39.33 % $ 11.20 April 20, 2010 2.6 % 5.00 1.5 % 39.10 % $ 8.14
Reconciliation of Denominators used in Computation of Basic and Diluted Earnings Per Share	The following tables present a reconciliation of the denominators used in the computation of basic and diluted earnings per share and a summary of the options to purchase shares of common stock which were excluded from the diluted earnings per share calculation because they were anti-dilutive: Nine-month Period Three-month Period Reconciliation 2018 2017 2018 2017 Basic weighted average shares outstanding 287,263,379 288,451,470 287,006,910 287,456,943 Weighted shares assumed upon exercise of stock options 195,029 140,104 256,312 121,100 Diluted weighted average shares outstanding 287,458,408 288,591,574 287,263,222 287,578,043
Anti-Dilutive Options Excluded	Nine-month Period Three-month Period Summary of Anti-dilutive Options Excluded 2018 2017 2018 2017 Options to purchase shares of common stock 1,597,342 3,881,605 1,534,795 3,848,126 Weighted average exercise price of options $ 55.02 49.21 $ 55.02 49.18

Debt Commitments (Tables)

Debt Commitments (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Schedule of Debt Obligations and Letters of Credit Outstanding	Debt obligations and letters of credit outstanding at the end of each period consisted of the following: September 30, 2018 December 31, 2017 Outstanding loans under unsecured revolving credit facility $ 255.0 280.0 2.00% Senior unsecured promissory note payable 40.0 40.0 2.45% Senior unsecured promissory note payable 35.0 35.0 3.22% Senior unsecured promissory note payable 60.0 60.0 Total debt 390.0 415.0 Less: Current portion of debt (2.5 ) (3.0 ) Long-term debt $ 387.5 412.0 Outstanding letters of credit under unsecured revolving credit facility - contingent obligation $ 36.3 36.3

Revenue - Revenues by Geographi

Revenue - Revenues by Geographic Areas (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues by Geographic Areas [Line Items]
Total revenues	$ 1,279.8	$ 1,132.8	$ 3,733.5	$ 3,302
United States
Revenues by Geographic Areas [Line Items]
Total revenues	1,104.9	989	3,226	2,897.4
Canada
Revenues by Geographic Areas [Line Items]
Total revenues	76.6	67	228.4	190.3
Other foreign countries
Revenues by Geographic Areas [Line Items]
Total revenues	$ 98.3	$ 76.8	$ 279.1	$ 214.3

Revenue - Percentages of Sales

Revenue - Percentages of Sales by End Market (Details) - End Market - Sales	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Percentage of Sales by End Market [Line Items]
Percentage of sales	100.00%	100.00%	100.00%	100.00%
Manufacturing
Percentage of Sales by End Market [Line Items]
Percentage of sales	66.40%	66.50%	66.70%	66.50%
Non-Residential construction
Percentage of Sales by End Market [Line Items]
Percentage of sales	13.40%	13.00%	13.10%	13.00%
Other
Percentage of Sales by End Market [Line Items]
Percentage of sales	20.20%	20.50%	20.20%	20.50%

Revenue - Percentages of Sale_2

Revenue - Percentages of Sales by Product Line (Details) - Product Line - Sales	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Percentage of Sales by Product Line [Line Items]
Percentage of sales	100.00%	100.00%	100.00%	100.00%
Fasteners
Percentage of Sales by Product Line [Line Items]
Percentage of sales	34.70%	35.60%	35.10%	35.80%
Tools
Percentage of Sales by Product Line [Line Items]
Percentage of sales	10.10%	10.30%	10.10%	10.10%
Cutting tools
Percentage of Sales by Product Line [Line Items]
Percentage of sales	5.70%	5.80%	5.70%	5.80%
Hydraulics & pneumatics
Percentage of Sales by Product Line [Line Items]
Percentage of sales	6.70%	6.70%	6.90%	6.80%
Material handling
Percentage of Sales by Product Line [Line Items]
Percentage of sales	5.70%	5.80%	5.80%	6.00%
Janitorial supplies
Percentage of Sales by Product Line [Line Items]
Percentage of sales	7.80%	7.40%	7.60%	7.30%
Electrical supplies
Percentage of Sales by Product Line [Line Items]
Percentage of sales	4.60%	4.80%	4.60%	4.90%
Welding supplies
Percentage of Sales by Product Line [Line Items]
Percentage of sales	4.10%	4.20%	4.10%	4.20%
Safety Supplies
Percentage of Sales by Product Line [Line Items]
Percentage of sales	17.30%	16.40%	17.00%	16.10%
Other
Percentage of Sales by Product Line [Line Items]
Percentage of sales	3.30%	3.00%	3.10%	3.00%

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Oct. 09, 2018	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation [Abstract]
Options vesting and exercisable period, maximum		8 years
Options termination period		9 years
Total stock-based compensation expense		$ 3.8	$ 4
Total unrecognized stock-based compensation expense		$ 14.9
Weighted average period over which total unrecognized stock-based compensation expense will be recognized		4 years 25 days
Subsequent Event
Subsequent Event [Line Items]
Dividend declared (in dollars per share)	$ 0.4

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Dividends Paid Previously or Declared (Details) - $ / shares	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
Dividends Per Share [Line Items]
Dividends paid (in dollars per share)		$ 0.4	$ 0.37	$ 0.37	$ 0.32	$ 0.32	$ 0.32	$ 0.32		$ 1.28
Forecast
Dividends Per Share [Line Items]
Dividends paid (in dollars per share)	$ 0.4								$ 1.54

Stockholders' Equity - Stock Op

Stockholders' Equity - Stock Options Granted (Details)	101 Months Ended
	Sep. 30, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	6,380,235
Options Outstanding (in shares)	4,071,702
Options Exercisable (in shares)	1,312,759
January 2, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	541,786
Option Exercise (Strike) Price (in dollars per share) | $ / shares	$ 55
Closing Stock Price on Date of Grant (in dollars per share) | $ / shares	$ 54.54
Options Outstanding (in shares)	525,525
Options Exercisable (in shares)	21,185
January 3, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	764,789
Option Exercise (Strike) Price (in dollars per share) | $ / shares	$ 47
Closing Stock Price on Date of Grant (in dollars per share) | $ / shares	$ 46.95
Options Outstanding (in shares)	683,528
Options Exercisable (in shares)	0
April 19, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	845,440
Option Exercise (Strike) Price (in dollars per share) | $ / shares	$ 46
Closing Stock Price on Date of Grant (in dollars per share) | $ / shares	$ 45.74
Options Outstanding (in shares)	706,116
Options Exercisable (in shares)	0
April 21, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	893,220
Option Exercise (Strike) Price (in dollars per share) | $ / shares	$ 42
Closing Stock Price on Date of Grant (in dollars per share) | $ / shares	$ 41.26
Options Outstanding (in shares)	630,784
Options Exercisable (in shares)	130,318
April 22, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	955,000
Option Exercise (Strike) Price (in dollars per share) | $ / shares	$ 56
Closing Stock Price on Date of Grant (in dollars per share) | $ / shares	$ 50.53
Options Outstanding (in shares)	519,750
Options Exercisable (in shares)	314,000
April 16, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	205,000
Option Exercise (Strike) Price (in dollars per share) | $ / shares	$ 54
Closing Stock Price on Date of Grant (in dollars per share) | $ / shares	$ 49.25
Options Outstanding (in shares)	91,249
Options Exercisable (in shares)	57,506
April 17, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	1,235,000
Option Exercise (Strike) Price (in dollars per share) | $ / shares	$ 54
Closing Stock Price on Date of Grant (in dollars per share) | $ / shares	$ 49.01
Options Outstanding (in shares)	828,750
Options Exercisable (in shares)	716,250
April 19, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	410,000
Option Exercise (Strike) Price (in dollars per share) | $ / shares	$ 35
Closing Stock Price on Date of Grant (in dollars per share) | $ / shares	$ 31.78
Options Outstanding (in shares)	52,850
Options Exercisable (in shares)	40,350
April 20, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	530,000
Option Exercise (Strike) Price (in dollars per share) | $ / shares	$ 30
Closing Stock Price on Date of Grant (in dollars per share) | $ / shares	$ 27.13
Options Outstanding (in shares)	33,150
Options Exercisable (in shares)	33,150

Stockholders' Equity - Fair Val

Stockholders' Equity - Fair Value Assumptions for Options Granted (Details)	9 Months Ended
	Sep. 30, 2018$ / shares
January 2, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free Interest Rate	2.20%
Expected Life of Option in Years	5 years
Expected Dividend Yield	2.30%
Expected Stock Volatility	23.45%
Estimated Fair Value of Stock Option (in dollars per share)	$ 10.03
January 3, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free Interest Rate	1.90%
Expected Life of Option in Years	5 years
Expected Dividend Yield	2.60%
Expected Stock Volatility	24.49%
Estimated Fair Value of Stock Option (in dollars per share)	$ 8.40
April 19, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free Interest Rate	1.30%
Expected Life of Option in Years	5 years
Expected Dividend Yield	2.60%
Expected Stock Volatility	26.34%
Estimated Fair Value of Stock Option (in dollars per share)	$ 8.18
April 21, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free Interest Rate	1.30%
Expected Life of Option in Years	5 years
Expected Dividend Yield	2.70%
Expected Stock Volatility	26.84%
Estimated Fair Value of Stock Option (in dollars per share)	$ 7.35
April 22, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free Interest Rate	1.80%
Expected Life of Option in Years	5 years
Expected Dividend Yield	2.00%
Expected Stock Volatility	28.55%
Estimated Fair Value of Stock Option (in dollars per share)	$ 9.57
April 16, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free Interest Rate	0.70%
Expected Life of Option in Years	5 years
Expected Dividend Yield	1.60%
Expected Stock Volatility	37.42%
Estimated Fair Value of Stock Option (in dollars per share)	$ 12.66
April 17, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free Interest Rate	0.90%
Expected Life of Option in Years	5 years
Expected Dividend Yield	1.40%
Expected Stock Volatility	39.25%
Estimated Fair Value of Stock Option (in dollars per share)	$ 13.69
April 19, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free Interest Rate	2.10%
Expected Life of Option in Years	5 years
Expected Dividend Yield	1.60%
Expected Stock Volatility	39.33%
Estimated Fair Value of Stock Option (in dollars per share)	$ 11.20
April 20, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free Interest Rate	2.60%
Expected Life of Option in Years	5 years
Expected Dividend Yield	1.50%
Expected Stock Volatility	39.10%
Estimated Fair Value of Stock Option (in dollars per share)	$ 8.14

Stockholders' Equity - Reconcil

Stockholders' Equity - Reconciliation of Denominators used in Computation of Basic and Diluted Earnings Per Share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Stockholders' Equity Note [Abstract]
Basic weighted average shares outstanding (in shares)	287,006,910	287,456,943	287,263,379	288,451,470
Weighted shares assumed upon exercise of stock options (in shares)	256,312	121,100	195,029	140,104
Diluted weighted average shares outstanding (in shares)	287,263,222	287,578,043	287,458,408	288,591,574

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Anti-Dilutive Options Excluded (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Stockholders' Equity Note [Abstract]
Options to purchase shares of common stock (in shares)	1,534,795	3,848,126	1,597,342	3,881,605
Weighted average exercise price of options (in dollars per share)	$ 55.02	$ 49.18	$ 55.02	$ 49.21

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Material changes in unrecognized tax benefits			$ 0
Income tax expense	$ 61.8	$ 82.9	$ 174.1	$ 246.1
Income tax expense, percent of earnings before income taxes			23.00%
Income tax benefit attributable to discrete income tax items			$ 10.3

Operating Leases - Additional I

Operating Leases - Additional Information (Details) $ in Millions	Sep. 30, 2018USD ($)
Leased Vehicles
Property Subject to or Available for Operating Lease [Line Items]
Aggregate residual value guarantee of pick-up leases	$ 83

Debt Commitments - Debt Obligat

Debt Commitments - Debt Obligations and Letters of Credit Outstanding (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Total debt	$ 390	$ 415
Less: Current portion of debt	(2.5)	(3)
Long-term debt	387.5	412
Credit Facility | Unsecured Revolving Credit Facility
Debt Instrument [Line Items]
Total debt	255	280
Credit Facility | Letter of Credit Subfacility
Debt Instrument [Line Items]
Outstanding letters of credit under unsecured revolving credit facility - contingent obligation	36.3	36.3
Senior Unsecured Promissory Notes | 2.00% Senior Unsecured Promissory Note Payable
Debt Instrument [Line Items]
Total debt	$ 40	40
Fixed interest rate per annum	2.00%
Senior Unsecured Promissory Notes | 2.45% Senior Unsecured Promissory Note Payable
Debt Instrument [Line Items]
Total debt	$ 35	35
Fixed interest rate per annum	2.45%
Senior Unsecured Promissory Notes | 3.22% Senior Unsecured Promissory Note Payable
Debt Instrument [Line Items]
Total debt	$ 60	$ 60
Fixed interest rate per annum	3.22%

Debt Commitments - Unsecured Re

Debt Commitments - Unsecured Revolving Credit Facility (Details) - Credit Facility	9 Months Ended
	Sep. 30, 2018USD ($)
Debt Instrument [Line Items]
Weighted per annum interest rate on outstanding line of credit	3.20%
Minimum
Debt Instrument [Line Items]
Percentage fee paid for unused portion of credit facility	0.10%
Maximum
Debt Instrument [Line Items]
Percentage fee paid for unused portion of credit facility	0.125%
LIBOR
Debt Instrument [Line Items]
Per annum interest rate over LIBOR	0.95%
Unsecured Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 700,000,000
Letter of Credit Subfacility
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 55,000,000

Debt Commitments - Senior Unsec

Debt Commitments - Senior Unsecured Promissory Notes Payable (Details) - Senior Unsecured Promissory Notes	Jul. 20, 2016USD ($)	Sep. 30, 2018USD ($)debt_instrument_series
Debt Instrument [Line Items]
Debt issuance period after effective date	3 years
Maximum aggregate principal amount outstanding	$ 200,000,000
Number of debt instrument series | debt_instrument_series		3
Fixed Rate Notes Payable
Debt Instrument [Line Items]
Term of debt (no later than 12 years)	12 years
Floating Rate Notes Payable
Debt Instrument [Line Items]
Term of debt (no later than 12 years)	10 years
2.00% Senior Unsecured Promissory Note Payable
Debt Instrument [Line Items]
Debt issuance, aggregate principal amount		$ 40,000,000
Fixed interest rate per annum		2.00%
2.45% Senior Unsecured Promissory Note Payable
Debt Instrument [Line Items]
Debt issuance, aggregate principal amount		$ 35,000,000
Fixed interest rate per annum		2.45%
3.22% Senior Unsecured Promissory Note Payable
Debt Instrument [Line Items]
Debt issuance, aggregate principal amount		$ 60,000,000
Fixed interest rate per annum		3.22%