Heartland Express (HTLD) 10-Q 9 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 07, 2019
Document Information [Line Items]
Entity Registrant Name	HEARTLAND EXPRESS INC
Entity Central Index Key	0000799233
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		81,979,305

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
CURRENT ASSETS
Cash and cash equivalents	$ 176,303	$ 161,448
Trade receivables, net of allowance of $0.9 million and $0.9 million	53,279	48,955
Prepaid tires	10,521	9,378
Other current assets	13,171	12,551
Income tax receivable	0	170
Total current assets	253,274	232,502
PROPERTY AND EQUIPMENT
Land and land improvements	53,518	46,095
Buildings	60,739	57,505
Leasehold improvements	437	437
Furniture and fixtures	3,093	3,057
Shop and service equipment	12,150	10,968
Revenue equipment	489,599	479,068
Construction in progress	2,235	6,540
Property, Plant and Equipment, Gross	621,771	603,670
Less accumulated depreciation	211,516	200,550
Property and equipment, net	410,255	403,120
GOODWILL	132,410	132,410
OTHER INTANGIBLES, NET	13,892	14,494
Deferred Income Taxes, Net	4,774	4,535
OTHER ASSETS	18,330	19,152
Assets	832,935	806,213
CURRENT LIABILITIES
Accounts payable and accrued liabilities	16,586	10,552
Compensation and benefits	22,659	22,558
Insurance accruals	21,123	22,130
Other accruals	11,552	9,449
Taxes Payable, Current	2,010	0
Total current liabilities	73,930	64,689
LONG-TERM LIABILITIES
Income taxes payable	5,317	5,577
Deferred income taxes, net	73,795	71,041
Insurance accruals less current portion	48,066	48,934
Total long-term liabilities	127,178	125,552
COMMITMENTS AND CONTINGENCIES (Note 15)
STOCKHOLDERS' EQUITY
Preferred stock, par value $.01; authorized 5,000 shares; none issued	0	0
Capital stock, common, $.01 par value; authorized 395,000 shares; issued 90,689 in 2019 and 2018; outstanding 81,943 in 2019 and 81,930 in 2018	907	907
Additional paid-in capital	3,424	3,454
Retained earnings	775,940	760,262
Treasury stock, at cost; 8,746 shares in 2019 and 8,759 in 2018	(148,444)	(148,651)
Stockholders' Equity Attributable to Parent	631,827	615,972
Liabilities and Stockholders' Equity	$ 832,935	$ 806,213

Consolidated Balance Sheets Con

Consolidated Balance Sheets Consolidated Balance Sheets (Parentheticals) - USD ($) shares in Thousands, $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Consolidated Balance Sheets Parentheticals [Abstract]
Allowance for Doubtful Accounts Receivable, Current	$ 0.9	$ 0.9
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	5,000	5,000
Preferred Stock, Shares Issued	0	0
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	395,000	395,000
Common Stock, Shares, Issued	90,689	90,689
Common Stock, Shares, Outstanding	81,943	81,930
Treasury Stock, Shares	8,746	8,759

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Operating Revenue	$ 139,536	$ 156,695
Operating Expenses
Salaries, wages, and benefits	53,796	62,009
Rent and purchased transportation	2,412	6,125
Fuel	23,180	28,940
Operating Costs and Expenses	5,845	7,865
Cost, Direct Tax and License	3,891	3,952
Insurance and claims	4,789	4,224
Communications and utilities	1,223	1,870
Depreciation and amortization	22,227	25,601
Other operating expenses	5,171	6,030
Gain on disposal of property and equipment	(3,841)	(2,869)
Total operating expenses	118,693	143,747
Operating income	20,843	12,948
Interest income	1,145	342
Income before income taxes	21,988	13,290
Federal and state income taxes	4,670	(88)
Net income	17,318	13,378
Other comprehensive income, net of tax	0	0
Comprehensive income	$ 17,318	$ 13,378
Net income per share
Basic	$ 0.21	$ 0.16
Diluted	$ 0.21	$ 0.16
Weighted average shares outstanding
Basic	81,936	83,309
Diluted	81,956	83,349
Dividends declared per share	$ 0.02	$ 0.02

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Capital Stock, Common	Additional Paid-in Capital	Retained Earnings	Treasury Stock
Balance at Dec. 31, 2017	$ 574,645	$ 907	$ 3,518	$ 694,174	$ (123,954)
Net income	13,378	0	0	13,378	0
Dividends on common stock, $0.02 per share	(1,667)	0	0	(1,667)	0
Repurchases of common stock	(1,293)	0	0	0	(1,293)
Stock-based compensation, net of tax	26	0	(104)	0	130
Balance at Mar. 31, 2018	585,089	907	3,414	705,885	(125,117)
Balance at Dec. 31, 2018	615,972	907	3,454	760,262	(148,651)
Net income	17,318	0	0	17,318	0
Dividends on common stock, $0.02 per share	(1,640)	0	0	(1,640)	0
Stock-based compensation, net of tax	177	0	(30)	0	207
Balance at Mar. 31, 2019	$ 631,827	$ 907	$ 3,424	$ 775,940	$ (148,444)

Consolidated Statement of Stock

Consolidated Statement of Stockholders' Equity Parentheticals - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Dividends declared per share	$ 0.02	$ 0.02

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
OPERATING ACTIVITIES
Net income	$ 17,318	$ 13,378
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	22,451	25,783
Deferred income taxes	2,515	5,184
Stock-based compensation	284	123
Gain on disposal of property and equipment	(3,841)	(2,869)
Changes in certain working capital items:
Trade receivables	(4,324)	2,722
Prepaid expenses and other current assets	(396)	(667)
Accounts payable, accrued liabilities, and accrued expenses	(158)	(6,106)
Accrued income taxes	1,920	(5,321)
Net cash provided by operating activities	35,769	32,227
INVESTING ACTIVITIES
Proceeds from sale of property and equipment	13,753	26,126
Purchases of property and equipment, net of trades	(34,209)	(32,018)
Change in other assets	4	436
Net cash used in investing activities	(20,452)	(5,456)
FINANCING ACTIVITIES
Payments of cash dividends	(1,640)	(1,667)
Shares withheld for employee taxes related to stock-based compensation	(107)	(97)
Repurchases of common stock	0	(1,293)
Net cash used in financing activities	(1,747)	(3,057)
Net increase in cash, cash equivalents and restricted cash	13,570	23,714
CASH, CASH EQUIVALENTS AND RESTRICTED CASH
Beginning of period	182,938	106,098
Ending Period	196,508	129,812
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Cash paid during the period for income taxes, net of refunds	235	46
Noncash investing and financing activities:
Purchased property and equipment in accounts payable	7,309	27,355
Sold revenue equipment in other current assets	4,611	11,746
RECONCILIATION OF CASH, CASH EQUIVALENTS AND RESTRICTED CASH
Cash and Cash Equivalents, at Carrying Value	176,303	105,019
Restricted Cash and Investments, Current	2,638	3,009
Restricted Cash and Cash Equivalents, Noncurrent	17,567	21,784
Ending Period	$ 196,508	$ 129,812

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2019
Basis of Presentation and Accounting Pronouncements [Abstract]
Basis of Presentation and Significant Accounting Policies [Text Block]	Basis of Presentation and New Accounting Pronouncements Heartland Express, Inc. is a holding company incorporated in Nevada, which owns all of the stock of Heartland Express, Inc. of Iowa, Heartland Express Services, Inc., and Heartland Express Maintenance Services, Inc. On July 6, 2017, Heartland Express, Inc. of Iowa acquired Interstate Distributor Co. ("IDC"), which was subsequently merged into Heartland Express, Inc. of Iowa effective October 1, 2017. Further, effective December 31, 2018, A & M Express, Inc. was merged into Heartland Express, Inc. of Iowa. We, together with our subsidiaries, are a short-to-medium haul truckload carrier (predominately 500 miles or less per load). We primarily provide nationwide asset-based dry van truckload service for major shippers from Washington to Florida and New England to California. The accompanying consolidated financial statements include the parent company, Heartland Express, Inc., and its subsidiaries, all of which are wholly owned. All material intercompany items and transactions have been eliminated in consolidation. The accompanying unaudited consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP") for interim financial information and with the instructions to Form 10-Q and Regulation S-X. Accordingly, they do not include all of the information and notes to the financial statements required by U.S. GAAP for complete financial statements. In the opinion of management, all normal, recurring adjustments considered necessary for a fair presentation have been included. The consolidated financial statements should be read in conjunction with the audited consolidated financial statements and accompanying notes for the year ended December 31, 2018 included in the Annual Report on Form 10-K of the Company filed with the Securities and Exchange Commission (the "SEC") on February 21, 2019. Interim results of operations are not necessarily indicative of the results to be expected for the full year or any other interim periods. There were no changes to the Company's significant accounting policies during the three month period ended March 31, 2019 . In August 2018, the SEC adopted the final rule under SEC Release No. 33-10532, "Disclosure Update and Simplification", streamlining certain disclosure requirements to reduce redundant, duplicative, or outdated disclosures. In addition, the amendments expand disclosures related to interim-period changes in stockholders’ equity and noncontrolling interests. Management has adopted and presented the expanded disclosures related to interim-period changes in stockholders' equity during the period ended March 31, 2019 . In January 2017, the Financial Accounting Standards Board ("FASB") issued ASU 2017-04, “Simplifying the Test for Goodwill Impairment,” which continues to require an entity to review indicators for impairment, perform qualitative assessments, and analyze the fair value of a reporting unit as compared to the carrying value of goodwill for potential impairment, but eliminates or replaces additional tests and assessments within the prior guidance. The provisions of this update are effective for fiscal years beginning after December 15, 2019, with early adoption permitted for impairment measurement tests occurring after January 1, 2017. Based on our assessment, we believe the impact of the early adoption of the standard will not have a material impact on our financial statements and therefore we intend to adopt the provisions of this standard in 2019 as part of our annual impairment test that will occur in September 2019. In June 2016, the FASB issued ASU 2016-13, "Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments". This update requires measurement and recognition of expected versus incurred credit losses for financial assets held. ASU 2016-13 is effective for annual periods beginning after December 15, 2019, and interim periods therein. Based on our initial assessment, we believe the impact of adoption of the standard will not have a material impact on our financial statements when adopted in 2020. In February 2016, the FASB issued ASU 2016-02, "Leases (Topic 842)". This update seeks to increase the transparency and comparability among entities by requiring public entities to recognize lease assets and lease liabilities on the balance sheet and disclose key information about leasing arrangements. To satisfy the standard’s objective, a lessee will recognize a right-of-use asset representing its right to use the underlying asset for the lease term and a lease liability for the obligation to make lease payments. Both the right-of-use asset and lease liability will initially be measured at the present value of the lease payments, with subsequent measurement dependent on the classification of the lease as either a finance or an operating lease. For leases with a term of twelve months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. If a lessee makes this election, it should recognize lease expense for such leases generally on a straight-line basis over the lease term.

Use of Estimates

Use of Estimates	3 Months Ended
	Mar. 31, 2019
Use of Estimates [Abstract]
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements in conformity with 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 financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. There were no significant changes in estimates and assumptions used by management related to our critical accounting policies during the three months ended March 31, 2019

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2019
Segment Information [Abstract]
Segment Information	Segment Information We provide truckload services across the United States (U.S.) and parts of Canada. These truckload services are primarily asset-based transportation services in the dry van truckload market. We also offer truckload temperature-controlled transportation services, although not significant to our operations. Our Chief Operating Decision Maker oversees and manages all of our transportation services, on a combined basis, including previously acquired entities. As a result of the foregoing, we have determined that we have one

Revenue Recognition (Notes)

Revenue Recognition (Notes)	3 Months Ended
	Mar. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Text Block]	Revenue Recognition The Company recognizes revenue over time as control of the promised services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those services. The delivery of the shipment and completion of the performance obligation allows for the collection of payment generally within 30 days after the delivery date of the shipment for the majority of our customers. The Company's operations are consistent with those in the trucking industry where freight is hauled twenty-four hours a day and seven days a week, subject to hours of service rules. The Company’s average length of haul is 400-500 miles per trip and each individual shipment accepted by the Company is considered a separate contract with the performance obligation being the delivery of the freight. Our average length of haul for each load of freight generally equals less than one day of continuous transit time. The Company estimates revenue for multiple-stop loads based on miles run and estimates revenue for single stop loads based on transit time, as the customer simultaneously receives and consumes the benefit provided. The Company hauls freight and earns revenue on a consistent basis throughout the periods presented. A corresponding contract asset existed for the estimated revenue of these in-process loads for $1.1 million and $1.1 million at March 31, 2019 and December 31, 2018 , respectively. Recorded contract assets are included in the accounts receivable line item of the balance sheet. Corresponding liabilities are recorded in the accounts payable and accrued liabilities and compensation and benefits line items for the estimated expenses on these same in-process loads. The Company had no contract liabilities associated with our operations as of March 31, 2019 . Total revenues recorded were $139.5 million and $156.7 million for the three months ended March 31, 2019 and 2018 , respectively. Fuel surcharge revenues were $17.0 million and $21.5 million for the three months ended March 31, 2019 and 2018 , respectively. Accessorial and other revenues recorded in the consolidated statements of comprehensive income collectively represented $2.8 million and $4.3 million for the three months ended March 31, 2019 and 2018 , respectively.

Cash and Cash Equivalents

Cash and Cash Equivalents	3 Months Ended
	Mar. 31, 2019
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents	Cash and Cash Equivalents Cash equivalents are short-term, highly liquid investments with insignificant interest rate risk and original maturities of three months or less at acquisition. At March 31, 2019 , restricted and designated cash and investments totaled $20.2 million , of which $2.6 million was included in other current assets and $17.6 million was included in other non-current assets in the consolidated balance sheet. Restricted and designated cash and investments totaled $21.5 million at December 31, 2018 , of which $3.1 million was included in other current assets and $18.4 million

Prepaid Tires, Property, Equipm

Prepaid Tires, Property, Equipment and Depreciation	3 Months Ended
	Mar. 31, 2019
Property, Plant and Depreciation [Abstract]
Property, Equipment, and Depreciation	Prepaid Tires, Property, Equipment, and Depreciation Property and equipment are reported at cost, net of accumulated depreciation. Maintenance and repairs are charged to operations as incurred. New tires are capitalized separately from revenue equipment and are reported separately as “Prepaid tires” in the consolidated balance sheets and amortized over two years . Depreciation for financial statement purposes is computed by the straight-line method for all assets other than tractors. We recognize depreciation expense on tractors using the 125% declining balance method. New tractors are depreciated to salvage values of $15,000 while new trailers are depreciated to salvage values of $4,000 . At March 31, 2019 , there was $4.6 million of amounts receivable related to equipment sales which was recorded in other current assets compared to $3.8 million

Other Intangible, Net and Goodw

Other Intangible, Net and Goodwill	3 Months Ended
	Mar. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets and Goodwill	Other Intangibles, Net and Goodwill All intangible assets determined to have finite lives are amortized over their estimated useful lives. The useful life of an intangible asset is the period over which the asset is expected to contribute directly or indirectly to future cash flows. There was no change in the gross amount of identifiable intangible assets during the three months ended March 31, 2019 . Amortization expense of $0.6 million and $0.7 million for the three months ended March 31, 2019 and 2018 respectively, was included in depreciation and amortization in the consolidated statements of comprehensive income. Intangible assets subject to amortization consisted of the following at March 31, 2019 : Amortization period (years) Gross Amount Accumulated Amortization Net intangible assets (in thousands) Customer relationships 20 $ 13,600 $ 2,500 $ 11,100 Tradename 0.5-6 8,100 7,329 771 Covenants not to compete 1-10 4,200 2,179 2,021 $ 25,900 $ 12,008 $ 13,892 The carrying amount of goodwill was $132.4 million

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Earnings Per Share	Earnings per Share Basic earnings per share is based upon the weighted average common shares outstanding during each year. Diluted earnings per share is based on the basic weighted earnings per share with additional weighted common shares for common stock equivalents. During the three months ended March 31, 2019 and March 31, 2018 , we had outstanding restricted shares of common stock to certain of our employees under the Company's 2011 Restricted Stock Award Plan (the "Plan"). A reconciliation of the numerator (net income) and denominator (weighted average number of shares outstanding of the basic and diluted earnings per share ("EPS")) for the three months ended March 31, 2019 and March 31, 2018 is as follows (in thousands, except per share data): Three months ended March 31, 2019 Net Income (numerator) Shares (denominator) Per Share Amount Basic EPS $ 17,318 81,936 $ 0.21 Effect of restricted stock — 20 Diluted EPS $ 17,318 81,956 $ 0.21 Three months ended March 31, 2018 Net Income (numerator) Shares (denominator) Per Share Amount Basic EPS $ 13,378 83,309 $ 0.16 Effect of restricted stock — 40 Diluted EPS $ 13,378 83,349 $ 0.16

Equity

Equity	3 Months Ended
	Mar. 31, 2019
Share Repurchases [Abstract]
Stockholders' Equity	Equity We have a stock repurchase program with 6.9 million shares remaining authorized for repurchase as of March 31, 2019 . There were no shares repurchased in the open market during the three months ended March 31, 2019 and there were 0.1 million shares repurchased during the same period in 2018 . Repurchases are expected to continue from time to time, as determined by market conditions, cash flow requirements, securities law limitations, and other factors, until the number of shares authorized have been repurchased, or until the authorization is terminated. The share repurchase authorization is discretionary and has no expiration date. During the three months ended March 31, 2019 and 2018 , our Board of Directors declared regular quarterly dividends totaling $1.6 million and $1.7 million

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2019
Stock-Based Compensation [Abstract]
Stock Based Compensation	Stock-Based Compensation In July 2011, a Special Meeting of Stockholders of Heartland Express, Inc. was held, at which meeting the approval of the Heartland Express, Inc. 2011 Restricted Stock Award Plan (the "Plan") was ratified. The Plan is administered by the Compensation Committee of our Board of Directors. Per the terms of the awards, employees receiving awards will have all of the rights of a stockholder with respect to the unvested restricted shares including, but not limited to, the right to receive such cash dividends, if any, as may be declared on such shares from time to time and the right to vote such shares at any meeting of our stockholders. The Plan made available up to 0.9 million shares for the purpose of making restricted stock grants to our eligible officers and employees. Shares granted in 2014 through 2019 have various vesting terms that range from immediate to four years from the date of grant. Once vested, there are no other restrictions on the awards. Compensation expense associated with these awards is based on the market value of our stock on the grant date. The Company's market close price ranged between $21.72 and $27.47 on the various grant dates during 2014, ranged between $19.93 and $27.29 on the various grant dates during 2015, ranged between $17.06 and $18.78 on the various grant dates during 2016, ranged between $20.53 and $23.37 on the various grant dates during 2017, and ranged between $18.12 and $19.03 on the various grant dates during 2018. The Company's market close price was $20.04 for the grant date during the three months ended March 31, 2019 . There were no significant assumptions made in determining the fair value. Compensation expense associated with restricted stock awards is included in salaries, wages and benefits in the consolidated statements of comprehensive income. Compensation expense associated with restricted stock awards was $0.3 million and $0.1 million respectively, for the three months ended March 31, 2019 and 2018 . Unrecognized compensation expense was $0.1 million at March 31, 2019 which will be recognized over a weighted average period of 0.9 year. The following tables summarize our restricted stock award activity for the three months ended March 31, 2019 and 2018 . Three Months Ended March 31, 2019 Number of Shares of Restricted Stock Awards (in thousands) Weighted Average Grant Date Fair Value Unvested at beginning of period 26.5 $ 21.31 Granted 12.5 20.04 Vested (18.5 ) 21.09 Forfeited (0.5 ) 17.11 Outstanding (unvested) at end of period 20.0 $ 20.82 Three Months Ended March 31, 2018 Number of Shares of Restricted Stock Awards (in thousands) Weighted Average Grant Date Fair Value Unvested at beginning of period 53.7 $ 21.82 Granted — — Vested (13.5 ) 24.86 Forfeited — — Outstanding (unvested) at end of period 40.2 $ 20.79

Long-Term Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2019
Line of Credit, Long-Term Debt [Abstract]
Long-Term Debt	Long-Term Debt In November 2013, Heartland Express, Inc. of Iowa, (the "Borrower"), a wholly owned subsidiary of the Company, entered into a Credit Agreement with Wells Fargo Bank, National Association, (the “Bank”). Pursuant to the Credit Agreement, the Bank provided a five-year, $250.0 million unsecured revolving line of credit which may be used for future working capital, equipment financing, and general corporate purposes. The Bank's original commitment decreased to $175.0 million on November 1, 2016 through scheduled maturity on October 31, 2018. However, on August 31, 2018, Borrower and the Bank entered into the First Amendment to this Credit Agreement. The First Amendment (i) provides for a $100.0 million unsecured revolving line of credit (the “Revolver”), which may be used for working capital, equipment financing, permitted acquisitions, and general corporate purposes, (ii) provides an uncommitted accordion feature, which allows the Company a one-time request, at the discretion of the Bank, to increase the Revolver by up to an additional $100.0 million , (iii) increases the letter of credit subfeature of the Credit Agreement from $20.0 million to $30.0 million , and (iv) extends the maturity of the Credit Agreement to August 31, 2021, subject to the Borrower’s ability to terminate the commitment at any time at no additional cost to the Borrower. The Credit Agreement is unsecured, with a negative pledge against all assets of our consolidated group, except for debt associated with permitted acquisitions, new purchase-money debt and capital lease obligations as described in the Credit Agreement. Borrowings under the Credit Agreement can either be, at Borrower's election, (i) one-month or three-month LIBOR (Index) plus a spread between 0.700% and 0.900% , based on the Company's consolidated funded debt to adjusted EBITDA ratio or (ii) Prime (Index) plus 0.0% . There is a commitment fee on the unused portion of the Revolver between 0.0725% and 0.1750% , based on the Company's consolidated funded debt to adjusted EBITDA ratio. The Credit Agreement contains customary financial covenants including, but not limited to, (i) a maximum adjusted leverage ratio of 2 :1, measured quarterly on a trailing twelve month basis, (ii) a minimum net income requirement of $1.00 , measured quarterly on a trailing twelve month basis, (iii) a minimum tangible net worth of $250.0 million requirement, measured quarterly, and (iv) limitations on other indebtedness and liens. The Credit Agreement also includes customary events of default, conditions, representations and warranties, and indemnification provisions. We were in compliance with the respective financial covenants at March 31, 2019 and during the three months then ended. We had no and no outstanding long-term debt at March 31, 2019 or December 31, 2018 , respectively. Outstanding letters of credit associated with the revolving line of credit at March 31, 2019 were $10.7 million . As of March 31, 2019 , the line of credit available for future borrowing was $89.3 million

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes We use the asset and liability method of accounting for income taxes. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statement carrying amount of existing assets and liabilities and their respective tax basis. 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. Such amounts are adjusted, as appropriate, to reflect changes in tax rates expected to be in effect when temporary differences reverse. The effect of changes in tax rates on deferred taxes is recognized in the period that the change is enacted. A valuation allowance is recorded to reduce the Company's deferred tax assets to the amount that is more likely than not to be realized. We had no recorded valuation allowance at March 31, 2019 and December 31, 2018 . Our effective tax rate was 21.2% and (0.7)% for the three months ended March 31, 2019 and 2018 , respectively. The changes in the effective tax rate are driven by less favorable provison to income tax return adjustments and a reduced value of uncertain tax positions reaching the statute of limitations. We recognize the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that is greater than 50% likely of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. We record interest and penalties related to unrecognized tax benefits in income tax expense. At March 31, 2019 and December 31, 2018 , we had a total of $4.5 million and $4.6 million in gross unrecognized tax benefits, respectively included in long-term income taxes payable in the consolidated balance sheet. Of this amount, $3.5 million and $3.6 million represents the amount of unrecognized tax benefits that, if recognized, would impact our effective tax rate as of March 31, 2019 and December 31, 2018 . The net decrease in unrecognized tax benefits was $0.1 million and a decrease of $1.2 million during the three months ended March 31, 2019 and 2018 , respectively. The net decrease during the the three months ended March 31, 2019 and 2018 , respectively, was mainly due to the expiration of certain statues of limitation net of additions and settlements with respective states. These changes had the corresponding increasing or decreasing impact on the effective state tax rate during these same periods. The total net amount of accrued interest and penalties for such unrecognized tax benefits was $0.9 million and $1.0 million at March 31, 2019 and December 31, 2018 and is included in long-term income taxes payable in the consolidated balance sheets. Income tax expense is increased each period for the accrual of interest on outstanding positions and penalties when the uncertain tax position is initially recorded. Income tax expense is reduced in periods by the amount of accrued interest and penalties associated with reversed uncertain tax positions due to lapse of applicable statute of limitations, when applicable or when a position is settled. Net interest and penalties included in income tax expense for the three month period ended March 31, 2019 and 2018 was a net benefit of approximately $0.1 million and $0.8 million , respectively. There was a favorable impact to income tax expense during the three months ended March 31, 2019 and 2018 due to reversals of interest and penalties due to lapse of applicable statute of limitations and settlements, net of additions for interest and penalty accruals during the same period. These unrecognized tax benefits relate to risks associated with state income tax filing positions for our corporate subsidiaries. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: 2019 (in thousands) Balance at January 1, 2019 $ 4,585 Additions based on tax positions related to current year 406 Additions for tax positions of prior years 124 Reductions for tax positions of prior years (60 ) Reductions due to lapse of applicable statute of limitations (533 ) Settlements (60 ) Balance at March 31, 2019 $ 4,462 A number of years may elapse before an uncertain tax position is audited and ultimately settled. It is difficult to predict the ultimate outcome or the timing of resolution for uncertain tax positions. It is reasonably possible that the amount of unrecognized tax benefits could significantly increase or decrease within the next twelve months. These changes could result from the expiration of the statute of limitations, examinations or other unforeseen circumstances. We do not have any outstanding litigation related to income tax matters. At this time, management’s best estimate of the reasonably possible change in the amount of gross unrecognized tax benefits to be a increase of approximately $0.1 million to an increase of $1.1 million during the next twelve months mainly due to the expiration of certain statute of limitations, net of additions. The federal statute of limitations remains open for the years 2016 and forward. Tax years 2008

Operating Leases

Operating Leases	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Operating Leases	Operating Leases Rent expense for operating leases for revenue equipment that resulted from our IDC acquisition was $0.3 million and $1.8 million for the three months ended March 31, 2019 and March 31, 2018 , respectively. These operating leases terminated March 31, 2019. These expenses were included in rent and purchased transportation in the consolidated statements of comprehensive income. We currently lease certain terminal facilities under operating leases and we expect these current leases to expire in 2019 and 2020. One of these leases contains a purchase option which we have exercised and expect to purchase during 2019. We are responsible for all taxes, insurance, and utilities related to the terminal leases. Rent expenses for terminal facilities were $0.8 million (including related-party rental payments totaling zero ), for the three months ended March 31, 2019 . Rent expenses for terminal facilities were $1.3 million (including related-party rental payments totaling $0.3 million ), for the three months ended March 31, 2018

Related Party

Related Party	3 Months Ended
	Mar. 31, 2019
Related Party [Abstract]
Related Party	Related Party We historically leased certain terminal facilities for operations under operating leases from certain limited liability companies, whose members include one of our board members and a commercial tractor dealership whose owners included one of our board members until the leases ended in November, 2018. We purchased parts and services from the commercial tractor dealership noted above. We owed the commercial tractor dealership $0.1 million and $0.1 million , included in accounts payable and accrued liabilities in the consolidated balance sheets at March 31, 2019 and December 31, 2018 , respectively. The payments with related parties for the three months ended March 31, 2019 and 2018 (in thousands) were as follows: Three months ended March 31, 2019 2018 Payments for parts and services $ 80 $ 136 Terminal lease payments — 247 $ 80 $ 383

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies We are a party to ordinary, routine litigation and administrative proceedings incidental to our business. In the opinion of management, our potential exposure under pending legal proceedings is adequately provided for in the accompanying consolidated financial statements. The total estimated purchase commitments for tractors (net of tractor sale commitments), trailer equipment, and exercised terminal purchase option as of March 31, 2019 was $82.5 million

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2019
Subsequent Events [Abstract]
Subsequent Events, Policy [Policy Text Block]	Subsequent Events

Basis of Presentation Basis of

Basis of Presentation Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2019
Basis of Presentation [Abstract]
Basis of Presentation [Policy Text Block]	Basis of Presentation and New Accounting Pronouncements Heartland Express, Inc. is a holding company incorporated in Nevada, which owns all of the stock of Heartland Express, Inc. of Iowa, Heartland Express Services, Inc., and Heartland Express Maintenance Services, Inc. On July 6, 2017, Heartland Express, Inc. of Iowa acquired Interstate Distributor Co. ("IDC"), which was subsequently merged into Heartland Express, Inc. of Iowa effective October 1, 2017. Further, effective December 31, 2018, A & M Express, Inc. was merged into Heartland Express, Inc. of Iowa. We, together with our subsidiaries, are a short-to-medium haul truckload carrier (predominately 500 miles or less per load). We primarily provide nationwide asset-based dry van truckload service for major shippers from Washington to Florida and New England to California. The accompanying consolidated financial statements include the parent company, Heartland Express, Inc., and its subsidiaries, all of which are wholly owned. All material intercompany items and transactions have been eliminated in consolidation. The accompanying unaudited consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP") for interim financial information and with the instructions to Form 10-Q and Regulation S-X. Accordingly, they do not include all of the information and notes to the financial statements required by U.S. GAAP for complete financial statements. In the opinion of management, all normal, recurring adjustments considered necessary for a fair presentation have been included. The consolidated financial statements should be read in conjunction with the audited consolidated financial statements and accompanying notes for the year ended December 31, 2018 included in the Annual Report on Form 10-K
New Accounting Pronouncements, Policy [Policy Text Block]	In August 2018, the SEC adopted the final rule under SEC Release No. 33-10532, "Disclosure Update and Simplification", streamlining certain disclosure requirements to reduce redundant, duplicative, or outdated disclosures. In addition, the amendments expand disclosures related to interim-period changes in stockholders’ equity and noncontrolling interests. Management has adopted and presented the expanded disclosures related to interim-period changes in stockholders' equity during the period ended March 31, 2019 . In January 2017, the Financial Accounting Standards Board ("FASB") issued ASU 2017-04, “Simplifying the Test for Goodwill Impairment,” which continues to require an entity to review indicators for impairment, perform qualitative assessments, and analyze the fair value of a reporting unit as compared to the carrying value of goodwill for potential impairment, but eliminates or replaces additional tests and assessments within the prior guidance. The provisions of this update are effective for fiscal years beginning after December 15, 2019, with early adoption permitted for impairment measurement tests occurring after January 1, 2017. Based on our assessment, we believe the impact of the early adoption of the standard will not have a material impact on our financial statements and therefore we intend to adopt the provisions of this standard in 2019 as part of our annual impairment test that will occur in September 2019. In June 2016, the FASB issued ASU 2016-13, "Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments". This update requires measurement and recognition of expected versus incurred credit losses for financial assets held. ASU 2016-13 is effective for annual periods beginning after December 15, 2019, and interim periods therein. Based on our initial assessment, we believe the impact of adoption of the standard will not have a material impact on our financial statements when adopted in 2020. In February 2016, the FASB issued ASU 2016-02, "Leases (Topic 842)". This update seeks to increase the transparency and comparability among entities by requiring public entities to recognize lease assets and lease liabilities on the balance sheet and disclose key information about leasing arrangements. To satisfy the standard’s objective, a lessee will recognize a right-of-use asset representing its right to use the underlying asset for the lease term and a lease liability for the obligation to make lease payments. Both the right-of-use asset and lease liability will initially be measured at the present value of the lease payments, with subsequent measurement dependent on the classification of the lease as either a finance or an operating lease. For leases with a term of twelve months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. If a lessee makes this election, it should recognize lease expense for such leases generally on a straight-line basis over the lease term.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates
Segment Reporting, Policy [Policy Text Block]	Segment Information We provide truckload services across the United States (U.S.) and parts of Canada. These truckload services are primarily asset-based transportation services in the dry van truckload market. We also offer truckload temperature-controlled transportation services, although not significant to our operations. Our Chief Operating Decision Maker oversees and manages all of our transportation services, on a combined basis, including previously acquired entities. As a result of the foregoing, we have determined that we have one segment, consistent with the authoritative accounting guidance on disclosures about segments of an enterprise and related information.
Revenue Recognition, Policy [Policy Text Block]	The Company recognizes revenue over time as control of the promised services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those services. The delivery of the shipment and completion of the performance obligation allows for the collection of payment generally within 30 days after the delivery date of the shipment for the majority of our customers.
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and Cash Equivalents
Property, Plant and Equipment, Policy [Policy Text Block]	Prepaid Tires, Property, Equipment, and Depreciation Property and equipment are reported at cost, net of accumulated depreciation. Maintenance and repairs are charged to operations as incurred. New tires are capitalized separately from revenue equipment and are reported separately as “Prepaid tires” in the consolidated balance sheets and amortized over two years . Depreciation for financial statement purposes is computed by the straight-line method for all assets other than tractors. We recognize depreciation expense on tractors using the 125% declining balance method. New tractors are depreciated to salvage values of $15,000 while new trailers are depreciated to salvage values of $4,000
Earnings Per Share, Policy [Policy Text Block]	Earnings per Share
Income Tax, Policy [Policy Text Block]	Income Taxes
Income Tax Uncertainties, Policy [Policy Text Block]	We recognize the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that is greater than 50%
Subsequent Events, Policy [Policy Text Block]	Subsequent Events

Other Intangible, Net and Goo_2

Other Intangible, Net and Goodwill (Tables)	3 Months Ended
	Mar. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite-Lived Intangible Assets [Table Text Block]	Amortization period (years) Gross Amount Accumulated Amortization Net intangible assets (in thousands) Customer relationships 20 $ 13,600 $ 2,500 $ 11,100 Tradename 0.5-6 8,100 7,329 771 Covenants not to compete 1-10 4,200 2,179 2,021 $ 25,900 $ 12,008 $ 13,892

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	Three months ended March 31, 2019 Net Income (numerator) Shares (denominator) Per Share Amount Basic EPS $ 17,318 81,936 $ 0.21 Effect of restricted stock — 20 Diluted EPS $ 17,318 81,956 $ 0.21 Three months ended March 31, 2018 Net Income (numerator) Shares (denominator) Per Share Amount Basic EPS $ 13,378 83,309 $ 0.16 Effect of restricted stock — 40 Diluted EPS $ 13,378 83,349 $ 0.16

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2019
Stock-Based Compensation [Abstract]
Disclosure of restricted stock award activity	The following tables summarize our restricted stock award activity for the three months ended March 31, 2019 and 2018 . Three Months Ended March 31, 2019 Number of Shares of Restricted Stock Awards (in thousands) Weighted Average Grant Date Fair Value Unvested at beginning of period 26.5 $ 21.31 Granted 12.5 20.04 Vested (18.5 ) 21.09 Forfeited (0.5 ) 17.11 Outstanding (unvested) at end of period 20.0 $ 20.82 Three Months Ended March 31, 2018 Number of Shares of Restricted Stock Awards (in thousands) Weighted Average Grant Date Fair Value Unvested at beginning of period 53.7 $ 21.82 Granted — — Vested (13.5 ) 24.86 Forfeited — — Outstanding (unvested) at end of period 40.2 $ 20.79

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Reconciliation of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: 2019 (in thousands) Balance at January 1, 2019 $ 4,585 Additions based on tax positions related to current year 406 Additions for tax positions of prior years 124 Reductions for tax positions of prior years (60 ) Reductions due to lapse of applicable statute of limitations (533 ) Settlements (60 ) Balance at March 31, 2019 $ 4,462

Related Party (Tables)

Related Party (Tables)	3 Months Ended
	Mar. 31, 2019
Related Party [Abstract]
Schedule of Related Party Transactions [Table Text Block]	The payments with related parties for the three months ended March 31, 2019 and 2018 (in thousands) were as follows: Three months ended March 31, 2019 2018 Payments for parts and services $ 80 $ 136 Terminal lease payments — 247 $ 80 $ 383

Segment Information (Details)

Segment Information (Details)	3 Months Ended
	Mar. 31, 2019segments
Segment Reporting Information [Line Items]
Number of Segments	1

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Contract with Customer, Asset, Net	$ 1,100		$ 1,100
Operating Revenue	139,536	$ 156,695
Revenue from Contract with Customer, Including Assessed Tax	2,800	4,300
fuel surcharge [Member]
Disaggregation of Revenue [Line Items]
Fuel surcharge revenue	$ 17,000	$ 21,500

Cash and Cash Equivalents (Deta

Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Property, Plant and Equipment [Line Items]
Restricted Cash and Cash Equivalents	$ 20,200	$ 21,500
Restricted Cash included in other current assets	2,638	3,100	$ 3,009
Restricted Cash included in other assets	$ 17,567	$ 18,400	$ 21,784

Prepaid Tires, Property, Equi_2

Prepaid Tires, Property, Equipment and Depreciation (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Amortization Period of Tires	2 years
Sold revenue equipment in other current assets	$ 4,600	$ 3,800
Tractors [Member]
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment, Salvage Value	15
Trailers [Member]
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment, Salvage Value	$ 4

Other Intangible, Net and Goo_3

Other Intangible, Net and Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Change In Gross Amount of Identifiable Intangible Assets	$ 0
Finite-Lived Intangible Assets, Amortization Expense	600	$ 700
Finite-Lived Intangible Assets [Line Items]
Carrying amount of goodwill	132,410		$ 132,410
Gross Amount	25,900
Accumulated Amortization	12,008
Net Intangible Assets	$ 13,892
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)	20 years
Gross Amount	$ 13,600
Accumulated Amortization	2,500
Net Intangible Assets	11,100
Tradename
Finite-Lived Intangible Assets [Line Items]
Gross Amount	8,100
Accumulated Amortization	7,329
Net Intangible Assets	771
Covenants Not to Compete
Finite-Lived Intangible Assets [Line Items]
Gross Amount	4,200
Accumulated Amortization	2,179
Net Intangible Assets	$ 2,021
Maximum [Member] | Tradename
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)	6 years
Maximum [Member] | Covenants Not to Compete
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)	10 years
Minimum [Member] | Tradename
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)	6 months
Minimum [Member] | Covenants Not to Compete
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)	1 year

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 17,318	$ 13,378
Basic EPS, Shares	81,936	83,309
Basic EPS, Per Share Amount	$ 0.21	$ 0.16
Effect of restricted stock	$ 0	$ 0
Effect of restricted stock, Shares	20	40
Diluted EPS, Net Income	$ 17,318	$ 13,378
Diluted EPS, Shares	81,956	83,349
Diluted EPS, Per Share Amount	$ 0.21	$ 0.16

Equity (Details)

Equity (Details) - USD ($) shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share Repurchases [Abstract]
Number of Shares Authorized to be Repurchased	6,900
Treasury Stock, Shares, Acquired	0	100
Dividends, Common Stock, Cash	$ 1.6	$ 1.7

Stock-Based Compensation (Detai

Stock-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jul. 11, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value price of stock awards lower			$ 18.12	$ 20.53	$ 17.06	$ 19.93	$ 21.72
weighted average fair value price of stock awards upper			$ 19.03	$ 23.37	$ 18.78	$ 27.29	$ 27.47
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	10 months 24 days
Restricted Stock Shares Authorized								900,000
Stock-based Compensation	$ 300	$ 100
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 100
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested at beginning of year, Number of Restricted Stock Awards (in shares)	26,500	53,700	53,700
Unvested at beginning of year, Weighted Average Grant Date Fair Value (in dollars)	$ 21.31	$ 21.82	$ 21.82
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period	12,500	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 20.04	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	(18,500)	(13,500)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$ 21.09	$ 24.86
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(500)	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 17.11	$ 0
Outstanding (unvested) at end of year, Number of Restricted Stock Awards (in shares)	20,000	40,200	26,500	53,700
Outstanding (unvested) at end of year, Weighted Average Grant Date Fair Value (in dollars)	$ 20.82	$ 20.79	$ 21.31	$ 21.82

Long-Term Debt (Details)

Long-Term Debt (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Nov. 01, 2016	Nov. 11, 2013
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity, Current	$ 100,000,000		$ 175,000,000	$ 250,000,000
Allowable Amount For Issuance of Letters of Credit	$ 30,000,000			$ 20,000,000
Debt Instrument, Covenant, Leverage Ratio	2
Debt Covenant, Minimum Net Income Requirement	$ 1
Debt Covenant, Minimum Tangible Net Worth	250,000,000
Long-term Debt	0	$ 0
Letters of Credit Outstanding, Amount	10,700,000
Line of Credit Facility, Current Borrowing Capacity	$ 89,300,000
Prime Rate [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.00%
Minimum [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.0725%
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.70%
Maximum [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.175%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.90%
Accordion Feature [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity, Current	$ 100,000,000

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Effective Income Tax Rate, Percent	21.20%	(0.70%)
Valuation Allowance [Abstract]
Valuation Allowance, Amount	$ 0		$ 0
Income Tax Uncertainties [Abstract]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	3,500		3,600
Unrecognized Tax Benefits, Period Increase (Decrease)	(100)	$ (1,200)
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	900		$ 1,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	(100)	$ (800)
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance beginning of period	4,585
Additions based on tax positions related to current year	406
Additions for tax positions of prior years	124
Reductions for tax positions of prior years	(60)
Reductions due to lapse of applicable statute of limitations	(533)
Settlements	(60)
Balance end of period	4,462
Maximum [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Lower Bound	1,100
Minimum [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Lower Bound	$ 100

Operating Leases (Details)

Operating Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating Leased Assets [Line Items]
Operating Leases, Rent Expense	$ 300	$ 1,800
Terminal Facilities
Operating Leased Assets [Line Items]
Operating Leases, Rent Expense	800	1,300
Terminal Facilities | Related Party
Operating Leased Assets [Line Items]
Operating Leases, Rent Expense	0	247
Related Party Transaction, Expenses from Transactions with Related Party	$ 0	$ 300

Related Party (Details)

Related Party (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Related Party Transaction [Line Items]
Due to Related Parties, Current	$ 100		$ 100
Operating Leases, Rent Expense	300	$ 1,800
Costs and Expenses, Related Party	80	383
Related Party
Related Party Transaction [Line Items]
Payments for parts and services	80	136
Terminal Facilities
Related Party Transaction [Line Items]
Operating Leases, Rent Expense	800	1,300
Terminal Facilities | Related Party
Related Party Transaction [Line Items]
Operating Leases, Rent Expense	$ 0	$ 247

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Millions	Mar. 31, 2019USD ($)
Commitments and Contingencies Disclosure [Abstract]
Unrecorded Unconditional Purchase Obligation	$ 82.5