Heartland Express (HTLD) 10-K 3 Mar 14 2013 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Feb. 28, 2014	Jun. 30, 2013
Document Information [Line Items]	'	'	'
Entity Registrant Name	'HEARTLAND EXPRESS INC	'	'
Entity Central Index Key	'0000799233	'	'
Document Type	'10-K	'	'
Document Period End Date	31-Dec-13	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Amendment Flag	'false	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Entity Common Stock, Shares Outstanding	'	87,704,993	'
Entity Public Float	'	'	$617.40

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
CURRENT ASSETS	'	'
Cash and cash equivalents	$17,763	$119,838
Trade receivables, net	84,400	46,555
Prepaid tires	6,999	6,603
Prepaid shop supplies	4,194	0
Other current assets	11,061	2,281
Income tax receivable	5,706	2,351
Deferred income taxes, net	14,177	13,797
Total current assets	144,300	191,425
PROPERTY AND EQUIPMENT	'	'
Land and land improvements	17,069	17,451
Buildings	27,347	26,761
Leasehold improvements	16,134	0
Furniture and fixtures	1,829	2,269
Shop and service equipment	10,604	7,266
Revenue equipment	549,415	378,583
Construction in progress	466	0
Property, Plant and Equipment, Gross	622,864	432,330
Less accumulated depreciation	173,605	189,959
Property and equipment, net	449,259	242,371
LONG-TERM INVESTMENTS	0	20,016
Goodwill	98,686	4,815
OTHER INTANGIBLES, NET	18,746	0
OTHER ASSETS	13,850	9,110
Assets	724,841	467,737
CURRENT LIABILITIES	'	'
Accounts payable and accrued liabilities	26,912	7,583
Compensation and benefits	28,084	16,409
Insurance accruals	20,945	13,924
Other accruals	12,627	7,439
Total current liabilities	88,568	45,355
LONG-TERM LIABILITIES	'	'
Income taxes payable	20,089	23,122
Long-term Debt	75,000	'
Long-term Debt, Excluding Current Maturities	75,000	0
Deferred income taxes, net	61,948	51,306
Insurance accruals less current portion	67,965	57,590
Other long-term liabilities	13,618	0
Total long-term liabilities	238,620	132,018
COMMITMENTS AND CONTINGENCIES (Note 9)	'	'
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 2012 and 2011; outstanding, 84,770 and 86,475 in 2012 and 2011, respectively	907	907
Additional paid-in capital	5,897	2,968
Retained earnings	432,034	368,313
Treasury stock, at cost; 5,919 and 4,214 shares in 2012 and 2011, respectively	-41,185	-80,540
Accumulated other comprehensive loss	0	-1,284
Stockholders' Equity Attributable to Parent	397,653	290,364
Liabilities and Stockholders' Equity	$724,841	$467,737

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets Parentheticals (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, except Per Share data, unless otherwise specified
Consolidated Balance Sheets Parentheticals [Abstract]	'	'
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	87,705	84,770
Treasury Stock, Shares	2,984	5,919

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Revenue	$582,257	$545,745	$528,623
Operating Expenses	'	'	'
Salaries, wages, and benefits	178,736	167,073	166,717
Rent and purchased transportation	12,808	6,273	7,527
Fuel	172,315	168,981	161,915
Operations and maintenance	22,345	25,282	20,938
Operating taxes and licenses	10,516	8,694	9,225
Insurance and claims	14,888	14,906	13,142
Communications and utilities	3,552	2,953	2,957
Depreciation and amortization	68,908	57,158	57,226
Other operating expenses	19,157	14,633	14,552
Gain on disposal of property and equipment	-33,270	-15,109	-32,133
Total operating expenses	469,955	450,844	422,066
Operating income	112,302	94,901	106,557
Interest income	462	674	773
Interest Expense	-208	0	0
Income before income taxes	112,556	95,575	107,330
Federal and state income taxes	41,974	34,034	37,398
Net income	70,582	61,541	69,932
Other comprehensive income, net of tax	1,284	1,797	0
Comprehensive income	$71,866	$63,338	$69,932
Net income per share	'	'	'
Basic	$0.83	$0.72	$0.78
Diluted	$0.83	$0.71	$0.78
Weighted average shares outstanding	'	'	'
Basic	85,209	85,892	89,656
Diluted	85,441	86,201	89,673
Dividends declared per share	$0.08	$1.08	$0.08

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity (USD $)	Total	Capital Stock, Common	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss
In Thousands
Balance at Dec. 31, 2010	$334,187	$907	$439	$335,922	$0	($3,081)
Net income	69,932	0	0	69,932	0	0
Other comprehensive income, net of tax	0	0	0	0	0	0
Dividends on common stock	-7,148	0	0	-7,148	0	0
Stock Issued During Period, Value, Treasury Stock Reissued	0	'	'	'	'	'
Repurchases of common stock	-56,350	0	0	0	-56,350	0
Stock-based Compensation	150	0	150	0	0	0
Balance at Dec. 31, 2011	340,771	907	589	398,706	-56,350	-3,081
Net income	61,541	0	0	61,541	0	0
Other comprehensive income, net of tax	1,797	0	0	0	0	1,797
Dividends on common stock	-91,934	0	0	-91,934	0	0
Stock Issued During Period, Value, Treasury Stock Reissued	0	'	'	'	'	'
Repurchases of common stock	-24,190	0	0	0	-24,190	0
Stock-based Compensation	2,379	0	2,379	0	0	0
Balance at Dec. 31, 2012	290,364	907	2,968	368,313	-80,540	-1,284
Net income	70,582	0	0	70,582	0	0
Other comprehensive income, net of tax	1,284	0	0	0	0	1,284
Dividends on common stock	-6,861	0	0	-6,861	0	0
Stock Issued During Period, Value, Treasury Stock Reissued	41,100	0	1,745	0	39,355	0
Stock-based Compensation	1,184	0	1,184	0	0	0
Balance at Dec. 31, 2013	$397,653	$907	$5,897	$432,034	($41,185)	$0

Consolidated_Statement_of_Stoc

Consolidated Statement of Stockholders' Equity Parentheticals (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Dividends declared per share	$0.08	$1.08	$0.08

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
OPERATING ACTIVITIES	'	'	'
Net income	$70,582	$61,541	$69,932
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'
Depreciation	69,649	57,821	57,876
Deferred income taxes	10,262	-5,751	14,743
Loss on sale of investments	200	0	0
Amortization of stock-based compensation	1,184	2,379	150
Gain on disposal of property and equipment	-33,270	-15,109	-32,133
Changes in certain working capital items:	'	'	'
Trade receivables	7,834	-2,357	-2,579
Prepaid expenses and other current assets	904	5,688	-6,459
Accounts payable, accrued liabilities, and accrued expenses	-9,722	953	-952
Accrued income taxes	-6,388	-2,992	-1,498
Net cash provided by operating activities	111,235	102,173	99,080
INVESTING ACTIVITIES	'	'	'
Proceeds from sale of property and equipment	92,313	29,184	73,018
Purchases of property and equipment, net of trades	-135,195	-66,811	-126,257
Maturity and calls of investments	21,100	32,350	38,125
Purchases of investments	-110,900	0	0
Change in other assets	-825	-704	-1,818
Net cash (used in) provided by investing activities	-133,507	-5,981	-16,932
FINANCING ACTIVITIES	'	'	'
Cash dividends	-6,861	-91,934	-7,148
Proceeds from Issuance of Long-term Debt	75,000	0	0
Repayment of long-term debt	-147,942	0	0
Repurchases of common stock	0	-24,190	-56,350
Net cash used in financing activities	-79,803	-116,124	-63,498
Net (decrease) increase in cash and cash equivalents	-102,075	-19,932	18,650
CASH AND CASH EQUIVALENTS	'	'	'
Beginning of period	119,838	139,770	121,120
End of period	17,763	119,838	139,770
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION	'	'	'
Interest Paid	4	0	0
Cash paid during the period for income taxes, net of refunds	38,101	42,776	24,152
Noncash investing and financing activities:	'	'	'
Fair value of revenue equipment traded	2,138	0	0
Purchased property and equipment in accounts payable	11,191	698	1,683
Issuance of common stock in acquisition of business	$41,100	$0	$0

Significant_Accounting_Policie

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
Significant Accounting Policies [Abstract]	'
Significant Accounting Policies	'
	Significant Accounting Policies
	Nature of Business
	Heartland Express, Inc., (the "Company") is a short-to-medium-haul truckload carrier of general commodities.  The Company provides nationwide transportation service to major shippers spanning from Washington to Florida and New England to California as well as parts of Canada. The Company provides these transportation services using Company controlled owned and leased revenue equipment as well as additional capacity through the use of independent contractor tractors.
	Principles of Consolidation
	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.
	Use of Estimates
	The preparation of the consolidated financial statements in conformity with U.S. generally accepted accounting principles (“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.
	Segment Information
	The Company provides multiple transportation services across the United States (U.S.) and parts of Canada through a nationwide network of regional operating divisions. The operating divisions are operated out of our regional office locations throughout the U.S. The Company offers asset-based transportation services in the dry van and temperature-controlled transportation markets as well as non-asset based brokerage services. Each of the divisions are managed based on similar economic characteristics. Each division provides services to a similar class of customers and are exposed to similar competitive and financial risk factors. As a result of the foregoing, the Company has determined that it is appropriate to aggregate its operating divisions into one reportable segment, consistent with the authoritative accounting guidance on disclosures about segments of an enterprise and related information. Accordingly, the Company has not presented separate segment financial information.
	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. Restricted and designated cash and investments totaled $10.6 million at December 31, 2013. As of December 31, 2013, $0.1 million is included in other current assets and $10.5 million is included in other non-current assets per the consolidated balance sheets.  Restricted and designated cash and investments totaled $9.1 million at December 31, 2012 and is included in non-current assets per the consolidated balance sheets. The restricted funds represent deposits required by state agencies for self-insurance purposes and designated funds that are earmarked for a specific purpose and not for general business use.
	Investments
	The Company determines the appropriate classification of the securities at the time they are acquired and evaluates the appropriateness of such classification at each balance sheet date.  As of December 31, 2013 the Company had no short-term or long-term investments classified as available-for-sale. As of December 31, 2012, the Company had classified its $20.0 million investment in auction rate securities as available-for-sale.  Available-for-sale securities, comprised entirely of auction rate securities, were stated at fair value, and unrealized holding gains and losses, net of the related deferred tax effect, were reported as a component of stockholders’ equity.  Realized gains and losses were determined on the basis of the specific securities sold.  Investments were reviewed quarterly for other-than-temporary impairments. During 2013, the Company received $21.1 million from calls and sales, reversed previously recorded accumulated other comprehensive losses associated with these investments of $1.3 million, and recognized a realized loss of $0.2 million with the sale of certain investments.
	Municipal bonds of $1.4 million and $1.3 million at December 31, 2013 and 2012, respectively, are stated at amortized cost, are classified as held-to-maturity and are included in restricted cash in other non-current assets.  Investment income received on available-for-sale and held-to-maturity investments is generally exempt from federal income taxes and is accrued as earned.
	Trade Receivables and Allowance for Doubtful Accounts
	Revenue is recognized when freight is delivered, creating a credit sale and an account receivable.  Credit terms for customer accounts are typically on a net 30 day basis.   The Company uses a percentage of aged receivable method and its write off history in estimating the allowance for bad debts.  The Company reviews the adequacy of its allowance for doubtful accounts on a monthly basis.  The Company is aggressive in its collection efforts resulting in a low number of write-offs annually.  Conditions that would lead an account to be considered uncollectible include customers filing bankruptcy and the exhaustion of all practical collection efforts.  The Company will use the necessary legal recourse to recover as much of the receivable as is practical under the law.  Allowance for doubtful accounts was $1.0 million and $0.8 million at December 31, 2013 and 2012, respectively.
	Prepaid Shop Supplies
	Prepaid shop supplies consist mainly of parts for revenue equipment and are valued at the lower of average cost or market.
	Property, Equipment, and Depreciation
	Property and equipment are reported at cost, net of accumulated depreciation. Maintenance and repairs are charged to operations as incurred.  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 expense of $0.7 million for the years ended December 31, 2013 and 2012 has been included in communication and utilities in the consolidated statements of comprehensive income. Depreciation for financial statement purposes is computed by the straight-line method for all assets other than tractors.  The Company recognizes depreciation expense on tractors at 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.
	The Company changed to 150% declining balance depreciation from the historical 125% declining balance depreciation for tractors in 2009 due to lower used truck values, higher prices for new equipment, and uncertainty surrounding the reliability and resale value of tractors with 2010 emission-compliant engines. Effective, July 1, 2013, the Company changed depreciation for tractors back to the historical 125% declining balance method as a stable used equipment market supported a return to the Company's historical estimate of depreciation on tractor equipment over its expected useful life. Under the declining balance method, depreciation for each tractor is highest in the first year and declines in each year throughout the useful life. Changing to the 125% declining balance method from the 150% declining balance method increased operating income and decreased depreciation expense by $4.4 million ($0.03 per share, net of tax effect) during the year ended December 31, 2013.
	Lives of the assets are as follows:
		Years
	Land improvements and buildings	30-May
	Leasehold improvements	25-May
	Furniture and fixtures	5-Mar
	Shop & service equipment	10-Mar
	Revenue equipment	7-May
	Impairment of Long-Lived Assets
	The Company periodically evaluates property and equipment and amortizable intangible assets for impairment upon the occurrence of events or changes in circumstances that indicate the carrying amount of assets may not be recoverable. Recoverability of assets to be held and used is evaluated by a comparison of the carrying amount of an asset group to future net undiscounted cash flows expected to be generated by the group. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount over which the carrying amount of the assets exceeds the fair value of the assets.  There were no impairment charges recognized during the years ended December 31, 2013, 2012, and 2011, respectively.
	Fair Value of Financial Instruments
	The fair values of cash and cash equivalents, trade receivables, held-to-maturity investments and accounts payable, which are recorded at cost, approximate fair value based on the short-term nature and high credit quality of these financial instruments. The fair value of long-term debt is equal to the carrying amount as all of the debt is variable rate debt at current market rates.
	Advertising Costs
	The Company expenses all advertising costs as incurred.  Advertising costs are included in other operating expenses in the consolidated statements of comprehensive income. Advertising expense was $0.9 million, $1.0 million, and $1.2 million for the years ended December 31, 2013, 2012, and 2011, respectively.
	Goodwill
	Goodwill is tested at least annually for impairment by applying a fair value based analysis in accordance with the authoritative accounting guidance on goodwill and other intangible assets.  The Company’s annual assessment is conducted as of the end of September each year and no other indicators requiring assessment were identified during the period from this assessment through year-end.  Management determined that no impairment charge was required for the years ended December 31, 2013, 2012, and 2011.
	Other Intangibles, Net
	Other intangibles, net consists primarily of tradenames, covenants not to compete, customer relationships, and real estate purchase options. 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. See notes 3 and 4 for additional information regarding intangible assets.
	Contingent Consideration
	The Company estimates and records the acquisition date estimated fair value of contingent consideration as part of purchase price consideration for acquisitions. Additionally, each reporting period, the Company estimates changes in the fair value of contingent consideration, and any change in fair value is recognized in the consolidated statements of comprehensive income. An increase in the earn-out expected to be paid will result in a charge to operations in the quarter that the anticipated fair value of contingent consideration increases, while a decrease in the earn-out expected to be paid will result in a credit to operations in the quarter that the anticipated fair value of contingent consideration decreases. The estimate of the fair value of contingent consideration requires subjective assumptions to be made of future operating results, discount rates, and probabilities assigned to various potential operating result scenarios. Future revisions to these assumptions could materially change the estimate of the fair value of contingent consideration and, therefore, materially affect the Company’s future financial results.
	Insurance Accruals
	The Company is self-insured for auto liability, cargo loss and damage, bodily injury and property damage (BI/PD), and workers’ compensation. Insurance accruals reflect the estimated cost of claims, including estimated loss and loss adjustment expenses incurred but not reported, and not covered by insurance.  Accident and workers’ compensation accruals are based upon individual case estimates, including reserve development, and estimates of incurred-but-not-reported losses based upon the Company's own historical experience and industry claim trends. Insurance accruals are not discounted. The cost of cargo and BI/PD insurance and claims are included in insurance and claims expense, while the costs of workers’ compensation insurance and claims are included in salaries, wages, and benefits in the consolidated statements of comprehensive income. Insurance accruals are presented as either current or non-current in the balance sheet based on the Company's expectation of when payment will occur.
	Health insurance accruals reflect the estimated cost of health related claims, including estimated expenses incurred but not reported.  The cost of health insurance and claims are included in salaries, wages and benefits in the consolidated statements of comprehensive income.  Health insurance accruals of $6.1 million and $3.7 million are included in other accruals in the consolidated balance sheets as of December 31, 2013 and 2012, respectively.
	Revenue and Expense Recognition
	Revenue is recognized when freight is delivered and is estimated for loads in transit at the end of an accounting period based on the number of miles run prior to end of the accounting period. Revenue associated with loads delivered but not billed as of the end of an accounting period are estimated as part of revenue for that period. Fuel surcharge revenue charged to customers is earned consistent with the timing of freight revenues and included in operating revenue in the consolidated statements of comprehensive income. Fuel surcharge revenues were $118.4 million, $112.4 million, and $107.8 million for the years ended December 31, 2013, 2012, and 2011, respectively. Driver wages and other direct operating expenses are recognized when freight is delivered and are estimated for loads in process at the end of an accounting period.
	Stock-based compensation
	The Company has a stock-based compensation plan that provides for the grants of restricted stock awards to employees of the Company. The Company accounts for restricted stock awards using the fair value method of accounting for stock-based compensation. Issuances of stock upon vesting of restricted stock are made from treasury stock. Compensation expense for restricted stock grants is recognized over the requisite service period of each award and is included in salaries, wages and benefits in the consolidated statements of comprehensive income. Total compensation of $5.2 million is being amortized over the requisite service period for each separate vesting period as if the award is, in substance, multiple awards.
	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 years ended December 31, 2011 and December 31, 2013 the Company granted shares of common stock to certain employees of the Company under the 2011 Restricted Stock Award 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 2013, 2012, and 2011 is as follows (in thousands, except per share data):
		2013
		Net Income (numerator)		Shares (denominator)	Per Share Amount
	Basic EPS	$	70,582	85,209	$	0.83
	Effect of restricted stock	—		232
	Diluted EPS	$	70,582	85,441	$	0.83
		2012
		Net Income (numerator)		Shares (denominator)	Per Share Amount
	Basic EPS	$	61,541	85,892	$	0.72
	Effect of restricted stock	—		309
	Diluted EPS	$	61,541	86,201	$	0.71
		2011
		Net Income (numerator)		Shares (denominator)	Per Share Amount
	Basic EPS	$	69,932	89,656	$	0.78
	Effect of restricted stock	—		17
Diluted EPS	$	69,932	89,673	$	0.78
Income Taxes
The Company uses 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 statements 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 the temporary differences reverse.  The effect of a change in tax rates on deferred taxes is recognized in the period that the change in 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.
Pursuant to the authoritative accounting guidance on income taxes, when establishing a valuation allowance, the Company considers future sources of taxable income such as “future reversals of existing taxable temporary differences and carry-forwards” and “tax planning strategies”.  In the event the Company determines that the deferred tax assets will not be realized in the future, the valuation adjustment to the deferred tax assets is charged to earnings or accumulated other comprehensive loss based on the nature of the asset giving rise to the deferred tax asset and the facts and circumstances resulting in that conclusion.
The Company calculates its current and deferred tax provision based on estimates and assumptions that could differ from the actual results reflected in income tax returns filed in subsequent years.  Adjustments based on filed returns are recorded when identified.
The Company recognizes 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.  The Company records interest and penalties related to unrecognized tax benefits in income tax expense.
Comprehensive Income
Comprehensive income consists of net income and other comprehensive income. Other comprehensive income refers to revenues, expenses, gains and losses that are not included in net income, but rather are recorded directly in stockholders' equity. For the years ended December 31, 2013, 2012, and 2011, comprehensive income consists of net income and unrealized gains on available-for-sale securities.
During the years ended December 31, 2013 and 2012 there was $1.3 million and $1.8 million, respectively, of income recorded directly in stockholders' equity related entirely to an unrealized gain on available for sale securities due to the reversal of a previously recorded reserve to adjust certain investments to estimated fair value based on calls of investments at par. During the year ended December 31, 2011 there were no amounts recorded directly in stockholders' equity and therefore there was no difference between net income and comprehensive income for this period.
Accounting Pronouncements
In February 2013, the FASB issued new accounting guidance which requires companies to provide information about the amounts reclassified out of accumulated other comprehensive income (loss) by component. In addition, a company is required to present significant amounts reclassified out of comprehensive income (loss) by the respective line items of net income. This guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2012. The Company adopted this guidance beginning with the Company's Quarterly Report on Form 10-Q for the period ending March 31, 2013. As the new standard did not change the current requirements for reporting net income or other comprehensive loss in the financial statements, the Company's financial position, results of operations or cash flows were not impacted by the adoption of this guidance.

Concentrations_of_Credit_Risk_

Concentrations of Credit Risk and Major Customers	12 Months Ended
	Dec. 31, 2013
Concentrations of Credit Risk and Major Customers [Abstract]	'
Concentration of Credit Risk and Major Customers	'
	Concentrations of Credit Risk and Major Customers
	The Company’s major customers represent primarily the consumer goods, appliances, food products and automotive industries.  Credit is granted to customers on an unsecured basis.  The Company’s five largest customers accounted for 32%, 39%, and 38% of total gross revenues for the years ended December 31, 2013, 2012 and 2011, respectively. The Company's five largest customers accounted for 20% and 31% of gross accounts receivable as of December 31, 2013 and 2012, respectively.
	There was no single customer that accounted for more than 10% of gross operating revenues for the year ended December 31, 2013. During the years ended December 31, 2012 and 2011 one customer exceeded 10% of total gross revenues. Annual revenues for this account for each of these years was $60.4 million, and $69.3 million, respectively.

Acquisition_of_Gordon_Trucking

Acquisition of Gordon Trucking, Inc. Acquisition of Gordon Trucking, Inc.	12 Months Ended
	Dec. 31, 2013
Acquisition of Gordon Trucking, Inc. [Abstract]	'
Acquisition of Gordon Trucking, Inc.	'
	Acquisition of Gordon Trucking, Inc.
	On November 11, 2013, Heartland Express, Inc. of Iowa (the "Buyer" or the "Borrower"), a wholly owned subsidiary of the Company, in its capacity as guarantor, entered into a Stock Purchase Agreement with Gordon Trucking, Inc., a Washington corporation ("GTI"), the stockholders of GTI (the "Sellers"), and Mr. Larry Gordon, in his capacity as Sellers' Representative. GTI is a truckload carrier headquartered near Seattle, Washington, offering local, regional, and trans-continental freight transportation.
	Pursuant to the Stock Purchase Agreement dated November 11, 2013, the Buyer purchased 100% of GTI's issued and outstanding common stock (the "Transaction"). The Buyer paid $285.0 million of total consideration, which was paid in cash, restricted shares of the Company's common stock, and the assumption of certain indebtedness of GTI. The cash portion of the consideration was funded pursuant to a promissory note due November 13, 2013 (two days after closing) to allow for movement of funds given that the closing occurred on a non-banking day. The purchase price remains subject to a post-closing true-up of working capital balances as well as other customary terms related to sellers representations. Up to an additional $20.0 million is payable in an earn-out for performance through 2017. The Stock Purchase Agreement included an election under the Internal Revenue Code Section 338(h)(10). In addition, the Buyer purchased the personal goodwill of Mr. Gordon for $15.0 million pursuant to an Asset Purchase Agreement. This personal goodwill is considered part of the total consideration for the Transaction.
	The Stock Purchase Agreement contained customary representations, warranties, covenants, and indemnification provisions. At closing, $24.0 million of the purchase price in the form of the Company's common stock was placed in escrow to secure payment of any post-closing adjustments to the purchase price and to secure the Sellers' indemnification obligations to the Buyer, and $6.0 million of the purchase price in cash was placed in escrow to secure the post-closing working capital adjustment.
	The funds to pay the cash consideration payable to the Sellers and Mr. Gordon was funded out of the Company's available cash at the time of the acquisition. The shares issued as part of the purchase price were issued from treasury shares. In connection with the Transaction, the Borrower, the Company, GTI, and the other members the Company's consolidated group entered into an unsecured revolving credit facility in the amount of up to $250.0 million (the "Financing"). Proceeds of the Financing were used in part to repay all of GTI's existing debt shortly after closing of the Transaction. See Note 5 for further details of the Financing.
	The results of the acquired business have been included in the consolidated financial statements since the date of acquisition and represented 48.6% of consolidated total assets as of December 31, 2013 and 9.6% of operating revenue for 2013. Acquisition related expenses of $2.2 million are included in the consolidated statement of comprehensive income for the year ended December 31, 2013.
	The following unaudited pro forma consolidated results of operations for the years ended December 31, 2013 and 2012 assume that the acquisition of GTI occurred as of January 1, 2012.
		Year ended
		31-Dec-12				31-Dec-13
		(in thousands)
	Operating revenue	$	972,340			$	961,525
	Net income	64,769				90,821
	These pro forma amounts do not purport to be indicative of the results that would have actually been obtained if the acquisition had occurred at the beginning of the periods presented or that may be obtained in the future.
	The allocation of the purchase price is detailed in the tables below. The final purchase price allocation remains subject to a post closing working capital adjustment, earn-out amounts achieved (if any), and other adjustments. The goodwill recognized represents expected synergies from combining the operations of the Company with GTI, as well as other intangible assets that did not meet the criteria for separate recognition. All tax goodwill recognized in the Transaction is deductible for tax purposes over 15 years.
	ALLOCATION OF PURCHASE PRICE	(in thousands)
	Cash paid (before netting $20 million cash acquired)				$	130,900
	Value of common stock issued (2.86 million shares)				41,100
	Total fair value of consideration transferred (before netting $20 million cash acquired), excluding debt assumed				172,000
	Allocated to:
	Historical book value of GTI's assets and liabilities	$	92,125
	Adjustments to recognize assets and liabilities at acquisition-date fair value:
	Property, plant, and equipment	(17,912		)
	Other assets	3,450
	Liabilities	(18,576		)
	Fair value of tangible net assets acquired				59,087
	Identifiable intangibles at acquisition-date fair value				19,042
	Excess of consideration transferred over the net amount of assets and liabilities recognized, including $13.6 million attributable to the fair value of a potential earn-out obligation (goodwill)				$	93,871
	Excess of consideration transferred over the net amount of assets and liabilities recognized, (goodwill), is still subject to final purchase price consideration related to post closing working capital adjustment.
	The assets and liabilities associated with GTI were recorded at their fair values as of the acquisition date and the amounts are as follows:
		(in thousands)
	Cash and cash equivalents	$	21,485
	Accounts receivable	45,679
	Other current assets	14,371
	Property and equipment	189,409
	Other non-current assets	3,916
	Intangible assets	19,042
	Goodwill	93,871
	Total assets	387,773
	Accounts payable and accrued expenses	(29,165		)
	Insurance accruals	(23,821		)
	Long-term debt	(147,942		)
	Other accruals	(14,845		)
	Total consideration transferred	$	172,000
	TOTAL PURCHASE PRICE CONSIDERATION	(in thousands)
	Cash paid pursuant to Stock Purchase Agreement	$	115,900
	Cash paid pursuant to an Asset Allocation Agreement	15,000
	Cash acquired included in historical book value of GTI assets and liabilities	(20,000		)
	Net cash paid at closing	$	110,900
	Common stock issued (par value of $0.01)	$	41,100
	Debt assumption	148,000
		$	300,000
	Included in adjustments to recognize assets and liabilities at acquisition-date fair values was a liability of $1.5 million, included in accounts payable and accrued liabilities as of December 31, 2013 representing a working capital adjustment for additional amounts owed to sellers for the cash balance delivered at closing that exceeded the estimated cash balance of $20.0 million paid at closing and debt balance delivered at closing that was less than the estimated debt balance of $148.0 million used in calculating the total purchase price consideration paid at closing.
	As part of Stock Purchase Agreement, the Company entered into a contingent consideration agreement with certain previous owners of GTI. The contingent consideration agreement includes various earn-out targets tied to operational performance of GTI as well as the Company over the period of 2014 through 2017. The total potential earn-out is $20.0 million with maximum amounts payable each year as follows:
			(in thousands)
	2014		$	6,000
	2015		6,000
	2016-2017		8,000
			$	20,000
	Per the terms of the Stock Purchase Agreement, the sellers will be entitled to any unearned earn-out amounts for 2014 and 2015 if the maximum earn-out target is achieved in either the 2016 or 2017 earn out period. The contingent liability was estimated as of the acquisition date and has been included in the adjustments to liabilities at acquisition-date fair value recorded. Estimated fair value of this contingent liability as of the acquisition date was calculated using unobservable, Level 3 inputs, due to lack of observable market inputs. The valuation of the contingent liability was generated by third party valuation personnel using a Monte Carlo, assuming Geometric Brownian Motion, simulation model to hypothetically replicate the Company's future performance model-based techniques that use significant assumptions not observable in the market including estimated future operating performance of the Company, a risk-free rate, volatility rate, and the underlying time period. As such, the fair value of the contingent liability is subject to change based on actual results of GTI and the Company in future years. The Company may be required to record an operating expense in a future period for any difference in the recorded liability, $13.6 million, included in other long-term liabilities at December 31, 2013 and the potential earn-out maximum payment of $20.0 million based on actual results.

Intangible_Assets_and_Goodwill

Intangible Assets and Goodwill	12 Months Ended
	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Intangible Assets and Goodwill	'
	Intangible Assets and Goodwill
	Intangible assets subject to amortization consist of the following at December 31, 2013. The Company did not have any intangible assets subject to amortization as of December 31, 2012.
		Amortization period (years)	Gross Amount		Accumulated Amortization		Net intangible assets
			(in thousands)
	Customer relationships	20	$	7,600	$	48	$	7,552
	Tradename	6	7,400		154		7,246
	Covenants not to compete	10	3,100		39		3,061
	Real estate options	2.2	942		55		887
			$	19,042	$	296	$	18,746
	Amortization expense associated with identifiable intangible assets at acquisition-date fair values from the date of acquisition to December 31, 2013 was $0.3 million and was included in depreciation and amortization per the consolidated statements of comprehensive income. Future amortization expense for intangible assets is estimated at $2.4 million the year ending December, 31, 2014, $2.4 million for 2015, $1.9 million for 2016, $1.9 million for 2017, and $1.9 million for 2018.
	Changes in carrying amount of goodwill were as follows:
		(in thousands)
	Balance at January 1, 2012	4,815
	Balance at December 31, 2012	4,815
	Acquisitions	93,871
	Balance at December 31, 2013	98,686

Line_of_Credit_and_Long_Term_D

Line of Credit and Long Term Debt (Notes)	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Line of Credit and Long Term Debt	'
	Long-Term Debt
	On November 11, 2013, the Company entered into a credit agreement by and among Wells Fargo Bank, National Association, (the "Bank"), Heartland Express, Inc. of Iowa (the "Borrower"), the Company, GTI, and the other members of the Company's consolidated group, as Guarantors (the "Credit Agreement"). Pursuant to the Credit Agreement, the Bank provided a five-year, $250.0 million unsecured revolving line of credit (the "Revolver"), which was used to assist in the repayment of debt assumed as part of the Transaction, and may be used in the future for working capital, equipment financing, and general corporate purposes. The Bank's commitment will decrease to $225.0 million on November 1, 2014, to $200.0 million on November 1, 2015, and to $175.0 million on November 1, 2016 through October 31, 2018.
	The Revolver is unsecured, with a negative pledge against all assets of the Company's consolidated group, except for debt associated with permitted acquisitions, new purchase-money debt and capital lease obligations as described in the Credit Agreement. The Revolver matures on October 31, 2018 (the "Maturity Date"). The Borrower has the ability to terminate the commitment at any time at no additional cost to the Borrower. Borrowings under the Credit Agreement can either be, at Borrower's election, (i) one-month or three-month LIBOR (Index) plus 0.625%, floating, or (ii) Prime (Index) plus 0.0%, floating. There is a commitment fee on the unused portion of the Revolver at 0.625%, due quarterly.
	The Credit Agreement contains customary financial covenants including, but not limited to, (i) a maximum adjusted leverage ratio of 2:1, measured quarterly, (ii) a minimum net income requirement of $1.00, measured quarterly, (iii) a minimum tangible net worth of $200 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. The Company was in compliance with the respective financial covenants at December 31, 2013.
	Long term debt consisted of the following at December 31 (in thousands):
		31-Dec-13
	Notes payable to Bank under the Revolver	$	75,000
	Long-term debt	$	75,000
	The weighted average variable annual percentage rate (“APR”) for amounts borrowed and outstanding at December 31, 2013 was 0.793%. Borrowing under the line of credit is recorded in "Long-term debt" in the consolidated balance sheets. Outstanding letters of credit associated with the Revolver at December 31, 2013 were $5.5 million. As of December 31, 2013, the line of credit available for future borrowing was $169.5 million.

Accident_and_Workers_Compensat

Accident and Workers' Compensation Insurance Liabilities	12 Months Ended
	Dec. 31, 2013
Accident and Workers' Compensation Insurance Liabilities [Abstract]	'
Accident and Workers' Compensation Insurance Liabilities	'
	Accident and Workers’ Compensation Insurance Accruals
	The Company acts as a self-insurer for auto liability involving property damage, personal injury, or cargo up to $2.0 million for any individual claim excluding GTI claims. Liabilities in excess of these amounts are covered by insurance up to $75.0 million in the aggregate for the coverage period, excluding GTI claims. The Company acts as a self-insurer for GTI auto liability involving property damage, personal injury, or cargo up to $0.5 million for any individual claim. Liabilities in excess of these amounts are covered by insurance up to $75.0 million.
	The Company acts as a self-insurer for workers’ compensation liability up to $1.0 million for any individual claim, excluding GTI claims. Liabilities in excess of this amount are covered by insurance.  The State of Iowa initially required the Company to deposit $0.7 million into a trust fund as part of the self-insurance program.  Earnings on this account become part of the required deposit and as of December 31, 2013 total deposits in this account were $1.4 million. This deposit is in municipal bonds classified as held-to-maturity and is recorded in other assets on the consolidated balance sheets.  The Company acts as a self-insurer for GTI workers' compensation liability up to $0.5 million. Liabilities in excess of this amount are covered by insurance. The State of Washington required GTI to deposit $0.7 million into a trust fund as part of the self insurance program. As of December 31, 2013, $0.6 million of deposits was recorded in other assets on the consolidated balance sheets.
	In addition, the Company has provided respective insurance carriers with letters of credit totaling approximately $8.7 million in connection with its liability and workers’ compensation insurance arrangements.  There were no outstanding balances due on the letters of credit at December 31, 2013 or 2012.
	Accident and workers’ compensation accruals include the estimated settlements, settlement expenses and an estimate for claims incurred but not yet reported for property damage, personal injury and public liability losses from vehicle accidents and cargo losses as well as workers’ compensation claims for amounts not covered by insurance.  Accident and workers’ compensation accruals are based upon individual case estimates, including reserve development, and estimates of incurred-but-not-reported losses based upon the Company's own historical experience and industry claim trends.  Since the reported liability is an estimate, the ultimate liability may be more or less than reported.  If adjustments to previously established accruals are required, such amounts are included in operating expenses in the current period.  These accruals are recorded on an undiscounted basis. Estimated claim payments to be made within one year of the balance sheet date have been classified as insurance accruals within current liabilities as of December 31, 2013 and 2012.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	Deferred tax assets and liabilities as of December 31, are as follows:
			2013				2012
			(in thousands)
	Deferred income tax assets:
	Allowance for doubtful accounts		$	291			$	305
	Accrued expenses		6,980				6,655
	Stock-based compensation		648				579
	Insurance accruals		26,000				27,549
	Unrealized loss on available-for-sale investments		—				449
	Indirect tax benefits of unrecognized tax benefits		4,846				5,658
	Other		1,889				1,011
	Total gross deferred tax assets		40,654				42,206
	Less valuation allowance		—				(449		)
	Net deferred tax assets		40,654				41,757
	Deferred income tax liabilities:
	Property and equipment		(85,849		)		(77,177		)
	Goodwill		(1,835		)		(1,351		)
	Prepaid expenses		(741		)		(738		)
			(88,425		)		(79,266		)
	Net deferred tax liability		$	(47,771	)		$	(37,509	)
	The deferred tax amounts above have been classified in the accompanying consolidated balance sheets at December 31, 2013 and 2012 as follows:
			2012				2011
			(in thousands)
	Current assets, net		$	14,177			$	13,797
	Long-term liabilities, net		(61,948		)		(51,306		)
			$	(47,771	)		$	(37,509	)
	The Company had no recorded valuation allowance at December 31, 2013 and $0.4 million at December 31, 2012, related to the Company’s deferred tax asset associated specifically with unrealized losses on auction rate securities. This valuation allowance was recorded as the Company did not have historical capital gains to generate capital gains sufficient to utilize the entire deferred tax asset generated by the fair value adjustment.  As the fair value adjustment was recorded through accumulated other comprehensive loss, the associated valuation allowance was also recorded through accumulated other comprehensive loss.  The above mentioned allowance did not impact the consolidated statement of comprehensive income for the years December 31, 2013, 2012, and 2011 as the deferred tax asset was fully reserved prior to changes in fair value adjustments recorded in 2013 and 2012.  The Company has not recorded a valuation allowance against any other deferred tax assets.  In management’s opinion, it is more likely than not that the Company will be able to utilize these deferred tax assets in future periods as a result of the Company’s history of profitability, taxable income, and reversal of deferred tax liabilities.
	Income tax expense consists of the following:
			2013				2012			2011
			(in thousands)
	Current income taxes:
	Federal		$	30,560			$	38,148		20,460
	State		1,152				1,636			2,195
			31,712				39,784			22,655
	Deferred income taxes:
	Federal		7,192				(5,890		)	16,587
	State		3,070				140			(1,844		)
			10,262				(5,750		)	14,743
	Total		$	41,974			$	34,034		$	37,398
	The income tax provision differs from the amount determined by applying the U.S. federal tax rate as follows:
			2013				2012			2011
			(in thousands)
	Federal tax at statutory rate (35%)		$	39,395			$	33,451		37,565
	State taxes, net of federal benefit		3,242				1,554			981
	Non-taxable interest income		(20		)		(48		)	(104		)
	Uncertain income tax penalties and interest, net		(766		)		(616		)	(1,159		)
	Other		123				(307		)	115
			$	41,974			$	34,034		$	37,398
	At December 31, 2013 and December 31, 2012, the Company had a total of $13.4 million and $15.7 million in gross unrecognized tax benefits, respectively.  Of this amount, $8.6 million and $10.1 million represents the amount of unrecognized tax benefits that, if recognized, would impact our effective tax rate as of December 31, 2013 and December 31, 2012.  Unrecognized tax benefits were a net decrease of $2.3 million and $0.3 million during the years ended December 31, 2013 and 2012, due mainly to the expiration of certain statutes of limitation net of additions and settlements with respective states.  This had the effect of reducing the effective state tax rate during these respective periods. The total net amount of accrued interest and penalties for such unrecognized tax benefits was $6.7 million and $7.4 million at December 31, 2013 and December 31, 2012 and is included in income taxes payable per the consolidated balance sheet.  Net interest and penalties included in income tax expense for the years ended December 31, 2013, 2012 and 2011 was a benefit of approximately $0.7 million, $0.6 million, and $1.2 million respectively. 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. Income tax expense was reduced during the years ended December 31, 2013, 2012 and 2011 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 the Company’s corporate subsidiaries.
	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:
		2013				2012
		(in thousands)
	Balance at January 1,	$	15,723			$	16,062
	Additions based on tax positions related to current year	843				1,146
	Additions for tax positions of prior years	616				1,075
	Reductions for tax positions of prior years	(300		)		(134		)
	Reductions due to lapse of applicable statute of limitations	(1,984		)		(2,426		)
	Settlements	(1,466		)		—
	Balance at December 31,	$	13,432			$	15,723
	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. The Company does not have any outstanding litigation related to 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 decrease of approximately $0.4 million to a decrease of $1.4 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 2010 and forward. Tax years 2003 and forward are subject to audit by state tax authorities depending on the tax code and administrative practice of each state.

Operating_Leases_Operating_Lea

Operating Leases Operating Leases	12 Months Ended
	Dec. 31, 2013
Leases [Abstract]	'
Operating Leases	'
	Operating Leases
	The Company has operating leases for certain revenue equipment. A portion of these leases are with a commercial tractor dealership, owned by a board member and certain employees of the Company. Rent expense for these leases were $1.3 million, (including related-party rental payments totaling $0.9 million) for the year ended December 31, 2013 and were included in rent and purchased transportation in the consolidated statements of comprehensive income. There was no rent expense in 2012. The various leases expire from 2014 through 2018.
	The Company leases certain terminal facilities under operating leases from limited liability companies, whose members include a board member and certain employees of the Company and a commercial tractor dealership owned by a board member and certain employees of the Company. The related-party rental payments were entered into as a result of the Transaction. Rent expense for terminal facilities were $0.7 million, including related-party rental payments totaling $0.6 million, for the year ended December 31, 2013 and were included in rent and purchased transportation in the consolidated statements of comprehensive income. There was no rent expense in 2012. The various leases expire from 2014 through 2018 and contain options to renew. The Company has purchase options on the majority of these facilities. The Company has a right of first refusal on the sale of the Pacific, Washington location property by the owners. The Company is responsible for all taxes, insurance, and utilities related to the terminal leases. See note 4 for acquisition-date fair value of the "Real estate options".
	The Company did not have any operating leases prior to 2013. Future minimum lease payments related to the leases described above, as of December 31, 2013, are as follows:
		Amount (in thousands)
		Related Party		Non-Related Party		Total
	2014	$	9,853	$	1,396	$	11,249
	2015	6,972		184		7,156
	2016	5,401		—		5,401
	2017	4,109		—		4,109
	2018	3,424		—		3,424
	Thereafter	—		—		—
	Total	$	29,759	$	1,580	$	31,339
	See note 12 for additional information.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2013
Share Repurchases [Abstract]	'
Stockholders' Equity	'
	Equity
	In September, 2001, the Board of Directors of the Company authorized a program to repurchase 15.4 million shares, adjusted for stock splits, of the Company’s common stock in open market or negotiated transactions using available cash, cash equivalents and investments.  There were 4.2 million shares repurchased in 2011 for $56.4 million. During February 2012, the Board of Directors increased the shares authorized for repurchase from the amount available to repurchase by approximately 2.8 million shares to a total of 5.0 million shares. As of December 31, 2012 there were approximately 3.2 million shares remaining authorized for repurchase under a repurchase program. There were no shares repurchased in the open market during the year ended December 31, 2013. During the year ended December 31, 2012, 1.8 million shares were repurchased for a total of $24.2 million, all of which were repurchased subsequent to the Board of Directors increased authorization in February 2012. The authorization remains open at December 31, 2013 and has no expiration date. Approximately 3.2 million shares remain authorized for repurchase under the program as of December 31, 2013. Shares repurchased during 2012 and 2011 were accounted for as treasury stock. Any shares purchased under the repurchase program prior to 2011 were retired. The repurchase program may be suspended or discontinued at any time without prior notice.
	During the years ended December 31, 2013, 2012 and 2011 the Company’s Board of Directors declared regular quarterly dividends totaling $6.9 million, $6.9 million, and $7.1 million for each year, respectively.  The Company paid a special dividend of $85.0 million during the fourth quarter of 2012. Future payment of cash dividends and the amount of such dividends will depend upon financial conditions, results of operations, cash requirements, tax treatment, and certain corporate law requirements, as well as factors deemed relevant by our Board of Directors.

StockBased_Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2013
Stock-Based Compensation [Abstract]	'
Stock Based Compensation	'
	Stock-Based Compensation
	On July 11, 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 the Company's Board of Directors (the "Committee"). In accordance with and subject to the provisions of the Plan, the Committee has the authority to determine all provisions of awards of restricted stock, including, without limitation, the employees of the Company who will receive awards, the number of shares awarded to individual employees, the time or times when awards will be granted, restrictions and other conditions (including, for example, the lapse of time) to which the vesting of awards may be subject, and other terms and conditions and form of agreement to be entered into by the Company and employees subject to awards of restricted stock. The Committee may allocate all or any portion of its responsibilities and powers under the Plan to any one or more of its members, the Chief Executive Officer, or other senior members of management as the Committee deems appropriate. 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 stockholders of the Company.
	The Plan made available up to 0.9 million shares for the purpose of making restricted stock grants to eligible officers and employees of the Company. During December 2011, 0.4 million shares were granted to employees and no additional shares were granted during 2012. There were 0.02 million shares granted during 2013. The shares granted under the Plan during 2011 are service based awards beginning December 14, 2011 and 20% of the awards vest each June 1st through 2016. The shares issued in 2013 are also service based awards and generally vest evenly from the date of grant through each June 1st through 2016. Once vested, there are no other restrictions on the awards. Compensation expense associated with these awards is based on the market value of the Company's stock on the grant date. The Company's market closing price on December 14, 2011, grant date, was $13.57 and ranged between $13.86 and $18.18 on the various grant dates for the shares issued in 2013. 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 $1.2 million, $2.4 million, and $0.2 million for the years ended December 31, 2013, 2012, and 2011 respectively. Unrecognized compensation expense was $1.2 million at December 31, 2013 which will be recognized over a weighted average period of 1.4 years. Unrecognized compensation expense will be recognized over a weighted average period of 1.8 years from the grant date of December 14, 2011 and total period of 4.5 years.
	The following table summarizes the Company's restricted stock award activity for the years ended December 31, 2013, 2012 and 2011. The vesting date for the majority of awards vested in 2013 was June 1, 2013. The fair value of awards vested during 2013 and 2012 was $1.1 million and $1.0 million, respectively.
		2013
		Number of Shares of Restricted Stock Awards (in thousands)		Weighted Average Grant Date Fair Value
	Unvested at beginning of year	276.8		$	13.57
	Granted	23		$	17.28
	Vested	(75.3	)	$	14.04
	Forfeited	(13.0	)	$	13.57
	Outstanding (unvested) at end of year	211.5		$	13.81
		2012
		Number of Shares of Restricted Stock Awards (in thousands)		Weighted Average Grant Date Fair Value
	Unvested at beginning of year	351		$	13.57
	Granted	—		$	—
	Vested	(70.2	)	$	13.57
	Forfeited	(4.0	)	$	13.57
	Outstanding (unvested) at end of year	276.8		$	13.57
		2011
		Number of Shares of Restricted Stock Awards (in thousands)		Weighted Average Grant Date Fair Value
	Unvested at beginning of year	—		$	—
	Granted	351		$	13.57
	Vested	—		$	—
	Forfeited	—		$	—
	Outstanding (unvested) at end of year	351		$	13.57

Profit_Sharing_Plan_and_Retire

Profit Sharing Plan and Retirement Plan	12 Months Ended
	Dec. 31, 2013
Profit Sharing Plan and Retirement Plan [Abstract]	'
Profit Sharing Plan and Retirement Plan	'
	Profit Sharing Plan and Retirement Plan
	The Company has retirement savings plans (the "Plans") for substantially all employees who have completed one year of service and are 19 years of age or older.  Employees may make 401(k) contributions subject to Internal Revenue Code limitations. The Plans provides for a discretionary profit sharing contribution to non-driver employees and a matching contribution of a discretionary percentage to driver employees (Heartland Plan) and discretionary matching contributions to driver and non-driver employees (GTI Plan).  Company profit sharing contributions totaled approximately $0.4 million, $0.7 million, and $0.8 million, for the years ended December 31, 2013, 2012 and 2011, respectively.

Related_Party

Related Party	12 Months Ended
	Dec. 31, 2013
Related Party [Abstract]	'
Related Party	'
	Related Party
	The Company leases terminal facilities for operations under operating leases from certain limited liability companies, whose members include a board member and certain employees of the Company and a commercial tractor dealership owned by a board member and certain employees of the Company. The terminal facility leases have initial five year terms with options to renew and options to purchase with the exception of the Pacific, Washington location which contains a right of first refusal on any sale of the property.
	The Company purchased tractors from and sold tractors to the commercial tractor dealership noted above. The Company has operating leases for certain revenue equipment with the commercial tractor dealership. The Company also purchased parts and services from the same commercial tractor dealership. The Company owed the commercial tractor dealership $1.3 million, included in accounts payable and accrued liabilities per the consolidated balance sheet at December 31, 2013, for tractors delivered but not paid for prior to December 31, 2013.
	The Company provides certain administrative services to the commercial tractor dealership. The related payments (receipts) with related parties for the period after the close of the Transaction, November 11, 2013, through December 31, 2013 were as follows:
		(in thousands)
	Payments for tractor purchases	$	6,884
	Receipts for tractor sales	(2,138		)
	Revenue equipment lease payments	930
	Payments for parts and services	1,058
	Terminal lease payments	572
	Administrative services receipts	(98		)
		$	7,208

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	The Company is a party to ordinary, routine litigation and administrative proceedings incidental to its business. In the opinion of management, the Company’s 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, and trailer equipment, at December 31, 2013, including amounts due on equipment received prior to December 31, 2013, but not paid for, was $79.5 million.

Quarterly_Financial_Informatio

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information (Unaudited) [Abstract]	'
Quarterly Financial Information (Unaudited)	'
	Quarterly Financial Information (Unaudited)
			First		Second		Third		Fourth
			(In Thousands, Except Per Share Data)
	Year ended December 31, 2013 (1)
	Operating revenue		$	134,273	$	133,992	$	130,645	$	183,348
	Operating income		30,207		29,375		26,000		26,720
	Income before income taxes		30,330		29,504		26,126		26,596
	Net income		19,734		19,138		15,868		15,842
	Net income per share, basic		0.23		0.23		0.19		0.18
	Net income per share, diluted		0.23		0.23		0.19		0.18
	Year ended December 31, 2012
	Operating revenue		$	134,833	$	139,710	$	135,010	$	136,192
	Operating income		23,778		26,748		19,667		24,708
	Income before income taxes		23,920		26,915		19,858		24,882
	Net income		16,588		18,227		12,434		14,292
	Net income per share, basic		0.19		0.21		0.15		0.17
	Net income per share, diluted		0.19		0.21		0.14		0.17
	-1	The Company acquired 100% of the outstanding stock of GTI on November 11, 2013 and therefore the operating results of the Company for the fourth quarter of 2013 includes the operating results of GTI for the period of November, 11, 2013 to December 31, 2013.

Subsequent_Events

Subsequent Events	12 Months Ended
	Dec. 31, 2013
Subsequent Events [Abstract]	'
Subsequent Events [Text Block]	'
	Subsequent Events
	The Company has evaluated events occurring subsequent to December 31, 2013 through the filing date of this Annual Report on Form 10-K for disclosure. No events occurred requiring disclosure.

Schedule_II_Valuation_of_Quali

Schedule II Valuation of Qualifying Accounts and Reserves

12 Months Ended

Dec. 31, 2013

Schedule II Valuation and Qualifying Accounts and Reserves [Abstract]

'

Schedule of Valuation and Qualifying Accounts Disclosure [Text Block]

'

SCHEDULE II

VALUATION AND QUALIFYING ACCOUNTS AND RESERVES

(In Thousands, Except Per Share Data)

Column A

Column B

Column C

Column D

Column E

Charges To

Balance At

Cost

Balance

Beginning

And

Other

At End

Description

of Period

Expense

Accounts (1)

Deductions

of Period

Allowance for doubtful accounts:

Year ended December 31, 2013

$

829

$

(27

)

$

238

$

12

$

1,028

Year ended December 31, 2012

791

205

—

167

829

Year ended December 31, 2011

775

83

—

67

791

(1) Addition to allowance for doubtful accounts following acquisition of GTI.

See accompanying Report of Independent Registered Public Accounting Firm.

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Significant Accounting Policies [Abstract]	'
Consolidation, Policy [Policy Text Block]	'
	Principles of Consolidation
	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.
Use of Estimates, Policy [Policy Text Block]	'
	Use of Estimates
	The preparation of the consolidated financial statements in conformity with U.S. generally accepted accounting principles (“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.
Segment Reporting, Policy [Policy Text Block]	'
	Segment Information
	The Company provides multiple transportation services across the United States (U.S.) and parts of Canada through a nationwide network of regional operating divisions. The operating divisions are operated out of our regional office locations throughout the U.S. The Company offers asset-based transportation services in the dry van and temperature-controlled transportation markets as well as non-asset based brokerage services. Each of the divisions are managed based on similar economic characteristics. Each division provides services to a similar class of customers and are exposed to similar competitive and financial risk factors. As a result of the foregoing, the Company has determined that it is appropriate to aggregate its operating divisions into one reportable segment, consistent with the authoritative accounting guidance on disclosures about segments of an enterprise and related information. Accordingly, the Company has not presented separate segment financial information.
Cash and Cash Equivalents, Policy [Policy Text Block]	'
	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. Restricted and designated cash and investments totaled $10.6 million at December 31, 2013. As of December 31, 2013, $0.1 million is included in other current assets and $10.5 million is included in other non-current assets per the consolidated balance sheets.  Restricted and designated cash and investments totaled $9.1 million at December 31, 2012 and is included in non-current assets per the consolidated balance sheets. The restricted funds represent deposits required by state agencies for self-insurance purposes and designated funds that are earmarked for a specific purpose and not for general business use.
Marketable Securities, Available-for-sale Securities, Policy [Policy Text Block]	'
	The Company determines the appropriate classification of the securities at the time they are acquired and evaluates the appropriateness of such classification at each balance sheet date.  As of December 31, 2013 the Company had no short-term or long-term investments classified as available-for-sale. As of December 31, 2012, the Company had classified its $20.0 million investment in auction rate securities as available-for-sale.  Available-for-sale securities, comprised entirely of auction rate securities, were stated at fair value, and unrealized holding gains and losses, net of the related deferred tax effect, were reported as a component of stockholders’ equity.  Realized gains and losses were determined on the basis of the specific securities sold.  Investments were reviewed quarterly for other-than-temporary impairments. During 2013, the Company received $21.1 million from calls and sales, reversed previously recorded accumulated other comprehensive losses associated with these investments of $1.3 million, and recognized a realized loss of $0.2 million with the sale of certain investments.
Marketable Securities, Held-to-maturity Securities, Policy [Policy Text Block]	'
	Municipal bonds of $1.4 million and $1.3 million at December 31, 2013 and 2012, respectively, are stated at amortized cost, are classified as held-to-maturity and are included in restricted cash in other non-current assets.  Investment income received on available-for-sale and held-to-maturity investments is generally exempt from federal income taxes and is accrued as earned.
Trade and Other Accounts Receivable, Policy [Policy Text Block]	'
	Trade Receivables and Allowance for Doubtful Accounts
	Revenue is recognized when freight is delivered, creating a credit sale and an account receivable.  Credit terms for customer accounts are typically on a net 30 day basis.   The Company uses a percentage of aged receivable method and its write off history in estimating the allowance for bad debts.  The Company reviews the adequacy of its allowance for doubtful accounts on a monthly basis.  The Company is aggressive in its collection efforts resulting in a low number of write-offs annually.  Conditions that would lead an account to be considered uncollectible include customers filing bankruptcy and the exhaustion of all practical collection efforts.  The Company will use the necessary legal recourse to recover as much of the receivable as is practical under the law.  Allowance for doubtful accounts was $1.0 million and $0.8 million at December 31, 2013 and 2012, respectively.
Inventory Supplies, Policy [Policy Text Block]	'
	Prepaid Shop Supplies
	Prepaid shop supplies consist mainly of parts for revenue equipment and are valued at the lower of average cost or market.
Property, Plant and Equipment, Policy [Policy Text Block]	'
	Property, Equipment, and Depreciation
	Property and equipment are reported at cost, net of accumulated depreciation. Maintenance and repairs are charged to operations as incurred.  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 expense of $0.7 million for the years ended December 31, 2013 and 2012 has been included in communication and utilities in the consolidated statements of comprehensive income. Depreciation for financial statement purposes is computed by the straight-line method for all assets other than tractors.  The Company recognizes depreciation expense on tractors at 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.
	The Company changed to 150% declining balance depreciation from the historical 125% declining balance depreciation for tractors in 2009 due to lower used truck values, higher prices for new equipment, and uncertainty surrounding the reliability and resale value of tractors with 2010 emission-compliant engines. Effective, July 1, 2013, the Company changed depreciation for tractors back to the historical 125% declining balance method as a stable used equipment market supported a return to the Company's historical estimate of depreciation on tractor equipment over its expected useful life. Under the declining balance method, depreciation for each tractor is highest in the first year and declines in each year throughout the useful life. Changing to the 125% declining balance method from the 150% declining balance method increased operating income and decreased depreciation expense by $4.4 million ($0.03 per share, net of tax effect) during the year ended December 31, 2013.
	Lives of the assets are as follows:
		Years
	Land improvements and buildings	30-May
	Leasehold improvements	25-May
	Furniture and fixtures	5-Mar
	Shop & service equipment	10-Mar
	Revenue equipment	7-May
Property, Plant and Equipment, Impairment [Policy Text Block]	'
	Impairment of Long-Lived Assets
	The Company periodically evaluates property and equipment and amortizable intangible assets for impairment upon the occurrence of events or changes in circumstances that indicate the carrying amount of assets may not be recoverable. Recoverability of assets to be held and used is evaluated by a comparison of the carrying amount of an asset group to future net undiscounted cash flows expected to be generated by the group. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount over which the carrying amount of the assets exceeds the fair value of the assets.  There were no impairment charges recognized during the years ended December 31, 2013, 2012, and 2011, respectively.
Fair Value of Financial Instruments, Policy [Policy Text Block]	'
	Fair Value of Financial Instruments
	The fair values of cash and cash equivalents, trade receivables, held-to-maturity investments and accounts payable, which are recorded at cost, approximate fair value based on the short-term nature and high credit quality of these financial instruments. The fair value of long-term debt is equal to the carrying amount as all of the debt is variable rate debt at current market rates.
Advertising Cost, Policy, Expensed Advertising Cost [Policy Text Block]	'
	Advertising Costs
	The Company expenses all advertising costs as incurred.  Advertising costs are included in other operating expenses in the consolidated statements of comprehensive income. Advertising expense was $0.9 million, $1.0 million, and $1.2 million for the years ended December 31, 2013, 2012, and 2011, respectively.
Goodwill and Intangible Assets, Policy [Policy Text Block]	'
	Goodwill
	Goodwill is tested at least annually for impairment by applying a fair value based analysis in accordance with the authoritative accounting guidance on goodwill and other intangible assets.  The Company’s annual assessment is conducted as of the end of September each year and no other indicators requiring assessment were identified during the period from this assessment through year-end.  Management determined that no impairment charge was required for the years ended December 31, 2013, 2012, and 2011.
Intangible Assets, Finite-Lived, Policy [Policy Text Block]	'
	Other Intangibles, Net
	Other intangibles, net consists primarily of tradenames, covenants not to compete, customer relationships, and real estate purchase options. 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. See notes 3 and 4 for additional information regarding intangible assets.
Commitments and Contingencies, Policy [Policy Text Block]	'
	Contingent Consideration
	The Company estimates and records the acquisition date estimated fair value of contingent consideration as part of purchase price consideration for acquisitions. Additionally, each reporting period, the Company estimates changes in the fair value of contingent consideration, and any change in fair value is recognized in the consolidated statements of comprehensive income. An increase in the earn-out expected to be paid will result in a charge to operations in the quarter that the anticipated fair value of contingent consideration increases, while a decrease in the earn-out expected to be paid will result in a credit to operations in the quarter that the anticipated fair value of contingent consideration decreases. The estimate of the fair value of contingent consideration requires subjective assumptions to be made of future operating results, discount rates, and probabilities assigned to various potential operating result scenarios. Future revisions to these assumptions could materially change the estimate of the fair value of contingent consideration and, therefore, materially affect the Company’s future financial results.
Self-insurance Policy Text Block [Policy Text Block]	'
	Insurance Accruals
	The Company is self-insured for auto liability, cargo loss and damage, bodily injury and property damage (BI/PD), and workers’ compensation. Insurance accruals reflect the estimated cost of claims, including estimated loss and loss adjustment expenses incurred but not reported, and not covered by insurance.  Accident and workers’ compensation accruals are based upon individual case estimates, including reserve development, and estimates of incurred-but-not-reported losses based upon the Company's own historical experience and industry claim trends. Insurance accruals are not discounted. The cost of cargo and BI/PD insurance and claims are included in insurance and claims expense, while the costs of workers’ compensation insurance and claims are included in salaries, wages, and benefits in the consolidated statements of comprehensive income. Insurance accruals are presented as either current or non-current in the balance sheet based on the Company's expectation of when payment will occur.
	Health insurance accruals reflect the estimated cost of health related claims, including estimated expenses incurred but not reported.  The cost of health insurance and claims are included in salaries, wages and benefits in the consolidated statements of comprehensive income.  Health insurance accruals of $6.1 million and $3.7 million are included in other accruals in the consolidated balance sheets as of December 31, 2013 and 2012, respectively.
Revenue Recognition, Policy [Policy Text Block]	'
	Revenue and Expense Recognition
	Revenue is recognized when freight is delivered and is estimated for loads in transit at the end of an accounting period based on the number of miles run prior to end of the accounting period. Revenue associated with loads delivered but not billed as of the end of an accounting period are estimated as part of revenue for that period. Fuel surcharge revenue charged to customers is earned consistent with the timing of freight revenues and included in operating revenue in the consolidated statements of comprehensive income. Fuel surcharge revenues were $118.4 million, $112.4 million, and $107.8 million for the years ended December 31, 2013, 2012, and 2011, respectively.
Cost of Sales, Policy [Policy Text Block]	'
	Driver wages and other direct operating expenses are recognized when freight is delivered and are estimated for loads in process at the end of an accounting period.
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]	'
	Stock-based compensation
	The Company has a stock-based compensation plan that provides for the grants of restricted stock awards to employees of the Company. The Company accounts for restricted stock awards using the fair value method of accounting for stock-based compensation. Issuances of stock upon vesting of restricted stock are made from treasury stock. Compensation expense for restricted stock grants is recognized over the requisite service period of each award and is included in salaries, wages and benefits in the consolidated statements of comprehensive income. Total compensation of $5.2 million is being amortized over the requisite service period for each separate vesting period as if the award is, in substance, multiple awards.
Earnings Per Share, Policy [Policy Text Block]	'
	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 years ended December 31, 2011 and December 31, 2013 the Company granted shares of common stock to certain employees of the Company under the 2011 Restricted Stock Award 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 2013, 2012, and 2011 is as follows (in thousands, except per share data):
		2013
		Net Income (numerator)		Shares (denominator)	Per Share Amount
	Basic EPS	$	70,582	85,209	$	0.83
	Effect of restricted stock	—		232
	Diluted EPS	$	70,582	85,441	$	0.83
		2012
		Net Income (numerator)		Shares (denominator)	Per Share Amount
	Basic EPS	$	61,541	85,892	$	0.72
	Effect of restricted stock	—		309
	Diluted EPS	$	61,541	86,201	$	0.71
		2011
		Net Income (numerator)		Shares (denominator)	Per Share Amount
	Basic EPS	$	69,932	89,656	$	0.78
	Effect of restricted stock	—		17
	Diluted EPS	$	69,932	89,673	$	0.78
Income Tax, Policy [Policy Text Block]	'
	Income Taxes
	The Company uses 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 statements 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 the temporary differences reverse.  The effect of a change in tax rates on deferred taxes is recognized in the period that the change in 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.
	Pursuant to the authoritative accounting guidance on income taxes, when establishing a valuation allowance, the Company considers future sources of taxable income such as “future reversals of existing taxable temporary differences and carry-forwards” and “tax planning strategies”.  In the event the Company determines that the deferred tax assets will not be realized in the future, the valuation adjustment to the deferred tax assets is charged to earnings or accumulated other comprehensive loss based on the nature of the asset giving rise to the deferred tax asset and the facts and circumstances resulting in that conclusion.
	The Company calculates its current and deferred tax provision based on estimates and assumptions that could differ from the actual results reflected in income tax returns filed in subsequent years.  Adjustments based on filed returns are recorded when identified.
Income Tax Uncertainties, Policy [Policy Text Block]	'
	The Company recognizes 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.  The Company records interest and penalties related to unrecognized tax benefits in income tax expense.
Stockholders' Equity, Policy [Policy Text Block]	'
	Comprehensive Income
	Comprehensive income consists of net income and other comprehensive income. Other comprehensive income refers to revenues, expenses, gains and losses that are not included in net income, but rather are recorded directly in stockholders' equity. For the years ended December 31, 2013, 2012, and 2011, comprehensive income consists of net income and unrealized gains on available-for-sale securities.
	During the years ended December 31, 2013 and 2012 there was $1.3 million and $1.8 million, respectively, of income recorded directly in stockholders' equity related entirely to an unrealized gain on available for sale securities due to the reversal of a previously recorded reserve to adjust certain investments to estimated fair value based on calls of investments at par. During the year ended December 31, 2011 there were no amounts recorded directly in stockholders' equity and therefore there was no difference between net income and comprehensive income for this period.
Description of New Accounting Pronouncements Not yet Adopted [Text Block]	'
	Accounting Pronouncements
	In February 2013, the FASB issued new accounting guidance which requires companies to provide information about the amounts reclassified out of accumulated other comprehensive income (loss) by component. In addition, a company is required to present significant amounts reclassified out of comprehensive income (loss) by the respective line items of net income. This guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2012. The Company adopted this guidance beginning with the Company's Quarterly Report on Form 10-Q for the period ending March 31, 2013. As the new standard did not change the current requirements for reporting net income or other comprehensive loss in the financial statements, the Company's financial position, results of operations or cash flows were not impacted by the adoption of this guidance.
Subsequent Events, Policy [Policy Text Block]	'
	Subsequent Events
	The Company has evaluated events occurring subsequent to December 31, 2013 through the filing date of this Annual Report on Form 10-K for disclosure.

Significant_Accounting_Policie2

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2013
Significant Accounting Policies [Abstract]	'
Property, Plant and Equipment [Table Text Block]	'
	Lives of the assets are as follows:
		Years
	Land improvements and buildings	30-May
	Leasehold improvements	25-May
	Furniture and fixtures	5-Mar
	Shop & service equipment	10-Mar
	Revenue equipment	7-May
Schedule of Calculation of Numerator and Denominator in Earnings Per Share [Table Text Block]	'
	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 2013, 2012, and 2011 is as follows (in thousands, except per share data):
		2013
		Net Income (numerator)		Shares (denominator)	Per Share Amount
	Basic EPS	$	70,582	85,209	$	0.83
	Effect of restricted stock	—		232
	Diluted EPS	$	70,582	85,441	$	0.83
		2012
		Net Income (numerator)		Shares (denominator)	Per Share Amount
	Basic EPS	$	61,541	85,892	$	0.72
	Effect of restricted stock	—		309
	Diluted EPS	$	61,541	86,201	$	0.71
		2011
		Net Income (numerator)		Shares (denominator)	Per Share Amount
	Basic EPS	$	69,932	89,656	$	0.78
	Effect of restricted stock	—		17
	Diluted EPS	$	69,932	89,673	$	0.78

Acquisition_of_Gordon_Trucking1

Acquisition of Gordon Trucking, Inc. (Tables)	12 Months Ended
	Dec. 31, 2013
Acquisition of Gordon Trucking, Inc. [Abstract]	'
Business Acquisition, Pro Forma Information [Table Text Block]	'
	The following unaudited pro forma consolidated results of operations for the years ended December 31, 2013 and 2012 assume that the acquisition of GTI occurred as of January 1, 2012.
		Year ended
		31-Dec-12				31-Dec-13
		(in thousands)
	Operating revenue	$	972,340			$	961,525
	Net income	64,769				90,821
Allocation of Purchase Price [Table Text Block]	'
	The allocation of the purchase price is detailed in the tables below. The final purchase price allocation remains subject to a post closing working capital adjustment, earn-out amounts achieved (if any), and other adjustments. The goodwill recognized represents expected synergies from combining the operations of the Company with GTI, as well as other intangible assets that did not meet the criteria for separate recognition. All tax goodwill recognized in the Transaction is deductible for tax purposes over 15 years.
	ALLOCATION OF PURCHASE PRICE	(in thousands)
	Cash paid (before netting $20 million cash acquired)				$	130,900
	Value of common stock issued (2.86 million shares)				41,100
	Total fair value of consideration transferred (before netting $20 million cash acquired), excluding debt assumed				172,000
	Allocated to:
	Historical book value of GTI's assets and liabilities	$	92,125
	Adjustments to recognize assets and liabilities at acquisition-date fair value:
	Property, plant, and equipment	(17,912		)
	Other assets	3,450
	Liabilities	(18,576		)
	Fair value of tangible net assets acquired				59,087
	Identifiable intangibles at acquisition-date fair value				19,042
	Excess of consideration transferred over the net amount of assets and liabilities recognized, including $13.6 million attributable to the fair value of a potential earn-out obligation (goodwill)				$	93,871
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	'
	The assets and liabilities associated with GTI were recorded at their fair values as of the acquisition date and the amounts are as follows:
		(in thousands)
	Cash and cash equivalents	$	21,485
	Accounts receivable	45,679
	Other current assets	14,371
	Property and equipment	189,409
	Other non-current assets	3,916
	Intangible assets	19,042
	Goodwill	93,871
	Total assets	387,773
	Accounts payable and accrued expenses	(29,165		)
	Insurance accruals	(23,821		)
	Long-term debt	(147,942		)
	Other accruals	(14,845		)
	Total consideration transferred	$	172,000
Total Purchase Price Consideration [Table Text Block]	'
	TOTAL PURCHASE PRICE CONSIDERATION	(in thousands)
	Cash paid pursuant to Stock Purchase Agreement	$	115,900
	Cash paid pursuant to an Asset Allocation Agreement	15,000
	Cash acquired included in historical book value of GTI assets and liabilities	(20,000		)
	Net cash paid at closing	$	110,900
	Common stock issued (par value of $0.01)	$	41,100
	Debt assumption	148,000
		$	300,000
Schedule of Business Acquisitions by Acquisition, Equity Interest Issued or Issuable [Table Text Block]	'
	The total potential earn-out is $20.0 million with maximum amounts payable each year as follows:
			(in thousands)
	2014		$	6,000
	2015		6,000
	2016-2017		8,000
			$	20,000

Intangible_Assets_and_Goodwill1

Intangible Assets and Goodwill (Tables)	12 Months Ended
	Dec. 31, 2013
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	$	7,600	$	48	$	7,552
	Tradename	6	7,400		154		7,246
	Covenants not to compete	10	3,100		39		3,061
	Real estate options	2.2	942		55		887
			$	19,042	$	296	$	18,746
Schedule of Goodwill [Table Text Block]	'
	Changes in carrying amount of goodwill were as follows:
		(in thousands)
	Balance at January 1, 2012	4,815
	Balance at December 31, 2012	4,815
	Acquisitions	93,871
	Balance at December 31, 2013	98,686

Line_of_Credit_and_Long_Term_D1

Line of Credit and Long Term Debt (Tables)	12 Months Ended
	Dec. 31, 2013
Line of Credit, Long-Term Debt [Abstract]	'
Schedule of Maturities of Long-term Debt [Table Text Block]	'
	Long term debt consisted of the following at December 31 (in thousands):
		31-Dec-13
	Notes payable to Bank under the Revolver	$	75,000
	Long-term debt	$	75,000

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	'
	Deferred tax assets and liabilities as of December 31, are as follows:
			2013				2012
			(in thousands)
	Deferred income tax assets:
	Allowance for doubtful accounts		$	291			$	305
	Accrued expenses		6,980				6,655
	Stock-based compensation		648				579
	Insurance accruals		26,000				27,549
	Unrealized loss on available-for-sale investments		—				449
	Indirect tax benefits of unrecognized tax benefits		4,846				5,658
	Other		1,889				1,011
	Total gross deferred tax assets		40,654				42,206
	Less valuation allowance		—				(449		)
	Net deferred tax assets		40,654				41,757
	Deferred income tax liabilities:
	Property and equipment		(85,849		)		(77,177		)
	Goodwill		(1,835		)		(1,351		)
	Prepaid expenses		(741		)		(738		)
			(88,425		)		(79,266		)
	Net deferred tax liability		$	(47,771	)		$	(37,509	)
Summary of Deferred Tax Assets (Liabilities) by Balance Sheet Classification [Table Text Block]	'
	The deferred tax amounts above have been classified in the accompanying consolidated balance sheets at December 31, 2013 and 2012 as follows:
			2012				2011
			(in thousands)
	Current assets, net		$	14,177			$	13,797
	Long-term liabilities, net		(61,948		)		(51,306		)
			$	(47,771	)		$	(37,509	)
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	'
	Income tax expense consists of the following:
			2013				2012			2011
			(in thousands)
	Current income taxes:
	Federal		$	30,560			$	38,148		20,460
	State		1,152				1,636			2,195
			31,712				39,784			22,655
	Deferred income taxes:
	Federal		7,192				(5,890		)	16,587
	State		3,070				140			(1,844		)
			10,262				(5,750		)	14,743
	Total		$	41,974			$	34,034		$	37,398
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	'
	The income tax provision differs from the amount determined by applying the U.S. federal tax rate as follows:
			2013				2012			2011
			(in thousands)
	Federal tax at statutory rate (35%)		$	39,395			$	33,451		37,565
	State taxes, net of federal benefit		3,242				1,554			981
	Non-taxable interest income		(20		)		(48		)	(104		)
	Uncertain income tax penalties and interest, net		(766		)		(616		)	(1,159		)
	Other		123				(307		)	115
			$	41,974			$	34,034		$	37,398
Reconciliation of Unrecognized Tax Benefits [Table Text Block]	'
	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:
		2013				2012
		(in thousands)
	Balance at January 1,	$	15,723			$	16,062
	Additions based on tax positions related to current year	843				1,146
	Additions for tax positions of prior years	616				1,075
	Reductions for tax positions of prior years	(300		)		(134		)
	Reductions due to lapse of applicable statute of limitations	(1,984		)		(2,426		)
	Settlements	(1,466		)		—
	Balance at December 31,	$	13,432			$	15,723

Operating_Leases_Operating_Lea1

Operating Leases Operating Leases (Tables)	12 Months Ended
	Dec. 31, 2013
Leases [Abstract]	'
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	'
	Future minimum lease payments related to the leases described above, as of December 31, 2013, are as follows:
		Amount (in thousands)
		Related Party		Non-Related Party		Total
	2014	$	9,853	$	1,396	$	11,249
	2015	6,972		184		7,156
	2016	5,401		—		5,401
	2017	4,109		—		4,109
	2018	3,424		—		3,424
	Thereafter	—		—		—
	Total	$	29,759	$	1,580	$	31,339

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2013
Stock-Based Compensation [Abstract]	'
Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block]	'
	The following table summarizes the Company's restricted stock award activity for the years ended December 31, 2013, 2012 and 2011. The vesting date for the majority of awards vested in 2013 was June 1, 2013. The fair value of awards vested during 2013 and 2012 was $1.1 million and $1.0 million, respectively.
		2013
		Number of Shares of Restricted Stock Awards (in thousands)		Weighted Average Grant Date Fair Value
	Unvested at beginning of year	276.8		$	13.57
	Granted	23		$	17.28
	Vested	(75.3	)	$	14.04
	Forfeited	(13.0	)	$	13.57
	Outstanding (unvested) at end of year	211.5		$	13.81
		2012
		Number of Shares of Restricted Stock Awards (in thousands)		Weighted Average Grant Date Fair Value
	Unvested at beginning of year	351		$	13.57
	Granted	—		$	—
	Vested	(70.2	)	$	13.57
	Forfeited	(4.0	)	$	13.57
	Outstanding (unvested) at end of year	276.8		$	13.57
		2011
		Number of Shares of Restricted Stock Awards (in thousands)		Weighted Average Grant Date Fair Value
	Unvested at beginning of year	—		$	—
	Granted	351		$	13.57
	Vested	—		$	—
	Forfeited	—		$	—
	Outstanding (unvested) at end of year	351		$	13.57

Related_Party_Tables

Related Party (Tables)	12 Months Ended
	Dec. 31, 2013
Related Party [Abstract]	'
Schedule of Related Party Transactions [Table Text Block]	'
	The Company provides certain administrative services to the commercial tractor dealership. The related payments (receipts) with related parties for the period after the close of the Transaction, November 11, 2013, through December 31, 2013 were as follows:
		(in thousands)
	Payments for tractor purchases	$	6,884
	Receipts for tractor sales	(2,138		)
	Revenue equipment lease payments	930
	Payments for parts and services	1,058
	Terminal lease payments	572
	Administrative services receipts	(98		)
		$	7,208

Quarterly_Financial_Informatio1

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information (Unaudited) [Abstract]	'
Schedule of Quarterly Financial Information [Table Text Block]	'
			First		Second		Third		Fourth
			(In Thousands, Except Per Share Data)
	Year ended December 31, 2013 (1)
	Operating revenue		$	134,273	$	133,992	$	130,645	$	183,348
	Operating income		30,207		29,375		26,000		26,720
	Income before income taxes		30,330		29,504		26,126		26,596
	Net income		19,734		19,138		15,868		15,842
	Net income per share, basic		0.23		0.23		0.19		0.18
	Net income per share, diluted		0.23		0.23		0.19		0.18
	Year ended December 31, 2012
	Operating revenue		$	134,833	$	139,710	$	135,010	$	136,192
	Operating income		23,778		26,748		19,667		24,708
	Income before income taxes		23,920		26,915		19,858		24,882
	Net income		16,588		18,227		12,434		14,292
	Net income per share, basic		0.19		0.21		0.15		0.17
	Net income per share, diluted		0.19		0.21		0.14		0.17
	-1	The Company acquired 100% of the outstanding stock of GTI on November 11, 2013 and therefore the operating results of the Company for the fourth quarter of 2013 includes the operating results of GTI for the period of November, 11, 2013 to December 31, 2013.

Significant_Accounting_Policie3

Significant Accounting Policies Segment Information (Details)	Dec. 31, 2013
	segments
Significant Accounting Policies [Abstract]	'
Numer of Segments	1

Significant_Accounting_Policie4

Significant Accounting Policies Cash and Cash Equivalents (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Significant Accounting Policies [Abstract]	'	'
Restricted Cash and Cash Equivalents	$10.60	$9.10
Restricted Cash and Investments, Current	0.1	'
Restricted Cash and Cash Equivalents, Noncurrent	$10.50	'

Significant_Accounting_Policie5

Significant Accounting Policies Investments (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Significant Accounting Policies [Abstract]	'	'	'
Available-for-sale Securities, Fair Value Disclosure	$0	$20,000,000	'
Proceeds from Maturities, Prepayments and Calls of Other Investments	21,100,000	32,350,000	38,125,000
Loss on sale of investments	200,000	0	0
Held-to-maturity Securities	$1,400,000	$1,300,000	'

Significant_Accounting_Policie6

Significant Accounting Policies Trade Receivables and Allowance for Doubtful Accounts (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified	D
Significant Accounting Policies [Abstract]	'	'
Customer credit terms (in days)	30	'
Allowance for Doubtful Accounts Receivable, Current	$1	$0.80

Significant_Accounting_Policie7

Significant Accounting Policies Property, Equipment and Depreciation (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment	'	'
Amortization Period of Tires	'2 years	'
Accumulated Depreciation, Depletion and Amortization, Property, Plant and Equipment, Period Increase (Decrease)	$4,400,000	'
change in estimate financial impact, per share, net of tax	0.03	'
Communications and Utilities Expense [Member]	'	'
Property, Plant and Equipment	'	'
Depreciation	700,000	700,000
Tractors [Member]	'	'
Property, Plant and Equipment	'	'
Property, Plant, and Equipment, Salvage Value	15,000	'
Trailers [Member]	'	'
Property, Plant and Equipment	'	'
Property, Plant, and Equipment, Salvage Value	$4,000	'
Minimum [Member] | Land Improvements and Buildings [Member]	'	'
Property, Plant and Equipment	'	'
Property, Plant and Equipment, Useful Life	'5 years	'
Minimum [Member] | Leasehold Improvements [Member]	'	'
Property, Plant and Equipment	'	'
Property, Plant and Equipment, Useful Life	'5 years	'
Minimum [Member] | Furniture and Fixtures [Member]	'	'
Property, Plant and Equipment	'	'
Property, Plant and Equipment, Useful Life	'3 years	'
Minimum [Member] | Shop and Service Equipment [Member]	'	'
Property, Plant and Equipment	'	'
Property, Plant and Equipment, Useful Life	'3 years	'
Minimum [Member] | Revenue Equipment [Member]	'	'
Property, Plant and Equipment	'	'
Property, Plant and Equipment, Useful Life	'5 years	'
Maximum [Member] | Land Improvements and Buildings [Member]	'	'
Property, Plant and Equipment	'	'
Property, Plant and Equipment, Useful Life	'30 years	'
Maximum [Member] | Leasehold Improvements [Member]	'	'
Property, Plant and Equipment	'	'
Property, Plant and Equipment, Useful Life	'25 years	'
Maximum [Member] | Furniture and Fixtures [Member]	'	'
Property, Plant and Equipment	'	'
Property, Plant and Equipment, Useful Life	'5 years	'
Maximum [Member] | Shop and Service Equipment [Member]	'	'
Property, Plant and Equipment	'	'
Property, Plant and Equipment, Useful Life	'10 years	'
Maximum [Member] | Revenue Equipment [Member]	'	'
Property, Plant and Equipment	'	'
Property, Plant and Equipment, Useful Life	'7 years	'

Significant_Accounting_Policie8

Significant Accounting Policies Impairment of Long-Lived Assets (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Significant Accounting Policies [Abstract]	'	'	'
Asset Impairment Charges	$0	$0	$0

Significant_Accounting_Policie9

Significant Accounting Policies Advertising Costs (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Significant Accounting Policies [Abstract]	'	'	'
Advertising Expense	$0.90	$1	$1.20

Recovered_Sheet1

Significant Accounting Policies Goodwill (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Significant Accounting Policies [Abstract]	'	'	'
Goodwill, Impairment Loss	$0	$0	$0

Recovered_Sheet2

Significant Accounting Policies Self-Insurance Accruals (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Significant Accounting Policies [Abstract]	'	'
Health insurance reserves	$6.10	$3.70

Recovered_Sheet3

Significant Accounting Policies Revenue and Expense Recognition (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Significant Accounting Policies [Abstract]	'	'	'
Fuel surcharge revenue	$118.40	$112.40	$107.80

Recovered_Sheet4

Significant Accounting Policies Stock-based compensation (Details) (USD $)	12 Months Ended			54 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	31-May-16
Significant Accounting Policies [Abstract]	'	'	'	'
Stock-based Compensation	$1,184	$2,379	$150	$5,200

Recovered_Sheet5

Significant Accounting Policies Earnings per Share (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Significant Accounting Policies [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Net income	$15,842	$15,868	$19,138	$19,734	$14,292	$12,434	$18,227	$16,588	$70,582	$61,541	$69,932
Weighted Average Number of Shares Outstanding, Basic	'	'	'	'	'	'	'	'	85,209	85,892	89,656
Basic EPS	$0.18	$0.19	$0.23	$0.23	$0.17	$0.15	$0.21	$0.19	$0.83	$0.72	$0.78
Dilutive Securities, Effect on Basic Earnings Per Share, Including Options and Restrictive Stock Units	'	'	'	'	'	'	'	'	0	0	0
Incremental Common Shares Attributable to Share-based Payment Arrangements	'	'	'	'	'	'	'	'	232	309	17
Net Income (Loss) Available to Common Stockholders, Diluted	'	'	'	'	'	'	'	'	$70,582	$61,541	$69,932
Weighted Average Number of Shares Outstanding, Diluted	'	'	'	'	'	'	'	'	85,441	86,201	89,673
Diluted EPS	$0.18	$0.19	$0.23	$0.23	$0.17	$0.14	$0.21	$0.19	$0.83	$0.71	$0.78

Recovered_Sheet6

Significant Accounting Policies Income Taxes (Details)	12 Months Ended
	Dec. 31, 2013
Significant Accounting Policies [Abstract]	'
PortionOfTaxBenefitRecordedPositionsMoreLikelyThanNotToBeSustained	50.00%

Recovered_Sheet7

Significant Accounting Policies Comprehensive Income (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Other comprehensive income, net of tax	$1,284	$1,797	$0
Accumulated Other Comprehensive Loss	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Other comprehensive income, net of tax	$1,284	$1,797	$0

Concentrations_of_Credit_Risk_1

Concentrations of Credit Risk and Major Customers (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
									Customer
Concentration Risk	'	'	'	'	'	'	'	'	'	'	'
Concentration of risk, number of customers	'	'	'	'	'	'	'	'	5	'	'
Entity-Wide Revenue, Major Customer, Amount	$183,348	$130,645	$133,992	$134,273	$136,192	$135,010	$139,710	$134,833	$582,257	$545,745	$528,623
Sales Revenue, Services, Net [Member] | Customer Concentration Risk [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Risk	'	'	'	'	'	'	'	'	'	'	'
Concentration of risk, number of customers	'	'	'	'	'	'	'	'	0	1	1
Baseline percentage for customer concentration of risk	'	'	'	'	'	'	'	'	10.00%	10.00%	10.00%
Concentration Risk, Percentage	'	'	'	'	'	'	'	'	32.00%	39.00%	38.00%
Entity-Wide Revenue, Major Customer, Amount	'	'	'	'	'	'	'	'	'	$60,400	$69,300
Accounts Receivable [Member] | Customer Concentration Risk [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Risk	'	'	'	'	'	'	'	'	'	'	'
Concentration Risk, Percentage	'	'	'	'	'	'	'	'	20.00%	31.00%	'

Acquisition_of_Gordon_Trucking2

Acquisition of Gordon Trucking, Inc. (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2017	Nov. 01, 2016	Dec. 31, 2015	Nov. 01, 2015	Dec. 31, 2014	Nov. 01, 2014	Nov. 11, 2013
Business Acquisition [Line Items]	'	'	'	'	'	'	'	'
Total acquisition purchase price	$300,000,000	'	'	'	'	'	'	'
Payments to Acquire Intangible Assets	-15,000,000	'	'	'	'	'	'	'
Fair Value of Stock in Escrow Related To Acquisition of Business	'	'	'	'	'	'	'	24,000,000
Fair Value of Cash in Escrow as a Result of Business Combination	'	'	'	'	'	'	'	6,000,000
Noncash or Part Noncash Acquisition, Debt Assumed	148,000,000	'	'	'	'	'	'	'
Line of Credit Facility, Maximum Borrowing Capacity	250,000,000	'	175,000,000	'	200,000,000	'	225,000,000	'
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	20,000,000	8,000,000	'	6,000,000	'	6,000,000	'	'
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	'	'	'	'	'	'	'	1,500,000
Cash Acquired from Acquisition	-20,000,000	'	'	'	'	'	'	'
Business Combination, Acquisition Related Costs	2,200,000	'	'	'	'	'	'	'
Gordon Trucking Company, Inc [Member]	'	'	'	'	'	'	'	'
Business Acquisition [Line Items]	'	'	'	'	'	'	'	'
Total acquisition purchase price	$285,000,000	'	'	'	'	'	'	'

Acquisition_of_Gordon_Trucking3

Acquisition of Gordon Trucking, Inc. Allocation of Purchase Price (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Business Acquisition [Line Items]	'	'
Cash Acquired from Acquisition	($20,000,000)	'
Cash paid (before netting $20 million cash acquired)	115,900,000	'
Stock Issued During Period, Shares, Acquisitions	2,860,000	'
Earn Out Agreement	13,600,000	'
Common Stock, Par or Stated Value Per Share	$0.01	$0.01
Gordon Trucking Company, Inc [Member]	'	'
Business Acquisition [Line Items]	'	'
Cash paid (before netting $20 million cash acquired)	130,900,000	'
Value of common stock issued (2.86 million shares)	41,100,000	'
Total fair value of consideration transferred (before netting $20 million cash acquired), excluding debt assumed	172,000,000	'
Historical book value of GTI assets and liabilities	92,125,000	'
Property, Plant, and Equipment	-17,912,000	'
Other assets	3,450,000	'
Liabilities	-18,576,000	'
Fair value of tangible net assets acquired	59,087,000	'
Identifiable intangibles at acquisition-date fair value	19,042,000	'
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	$93,871,000	'

Acquisition_of_Gordon_Trucking4

Acquisition of Gordon Trucking, Inc. Total Purchase Price Consideration (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Acquisition of Gordon Trucking, Inc [Abstract]	'	'	'
Payments to Acquire Businesses, Gross	$115,900	'	'
Payments to Acquire Intangible Assets	15,000	'	'
Cash Acquired from Acquisition	-20,000	'	'
Payments to Acquire Businesses, Net of Cash Acquired	110,900	0	0
Business Combination, Acquisition Related Costs	148,000	'	'
Common stock issued (par value of $0.01)	41,100	'	'
Total acquisition purchase price	$300,000	'	'

Acquisition_of_Gordon_Trucking5

Acquisition of Gordon Trucking, Inc. Potential Earn Out Schedule (Details) (USD $)	Dec. 31, 2017	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Acquisition of Gordon Trucking [Abstract]	'	'	'	'
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	$8,000,000	$6,000,000	$6,000,000	$20,000,000
Earn Out Agreement	'	'	'	$13,600,000

Acquisition_of_Gordon_Trucking6

Acquisition of Gordon Trucking, Inc. Assets acquired and liabilities assumed (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Nov. 11, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Business Acquisition [Line Items]	'	'	'	'	'
Assets of business combination as percentage total assets	0.486	'	'	'	'
Business Acquisition, Percentage of Voting Interests Acquired	'	100.00%	'	'	'
Cash and cash equivalents	$17,763	'	$119,838	$139,770	$121,120
Other current assets	11,061	'	2,281	'	'
Property, Plant and Equipment, Gross	622,864	'	432,330	'	'
Other Assets, Noncurrent	13,850	'	9,110	'	'
Finite-Lived Intangible Assets, Gross	19,042	'	'	'	'
Goodwill	98,686	'	4,815	4,815	'
Assets	724,841	'	467,737	'	'
Long-term Debt	75,000	'	'	'	'
Other long-term liabilities	13,618	'	0	'	'
Revenues of business combination as percentage of total revenues	0.096	'	'	'	'
Gordon Trucking Company, Inc [Member]	'	'	'	'	'
Business Acquisition [Line Items]	'	'	'	'	'
Cash and cash equivalents	'	21,485	'	'	'
Accounts Receivable, Net	'	45,679	'	'	'
Other current assets	'	14,371	'	'	'
Property, Plant and Equipment, Gross	'	189,409	'	'	'
Other Assets, Noncurrent	'	3,916	'	'	'
Finite-Lived Intangible Assets, Gross	'	19,042	'	'	'
Goodwill	'	93,871	'	'	'
Assets	'	387,773	'	'	'
Accounts Payable and Accrued Liabilities	'	-29,165	'	'	'
Self Insurance Reserve	'	-23,821	'	'	'
Long-term Debt	'	-147,942	'	'	'
Other long-term liabilities	'	-14,845	'	'	'
Total consideration transferred to acquire a business	$172,000	'	'	'	'

Acquisition_of_Gordon_Trucking7

Acquisition of Gordon Trucking, Inc. Acquisition pro forma information (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Acquisition of Gordon Trucking, Inc. [Abstract]	'	'
Business Acquisition, Pro Forma Revenue	$961,525	$972,340
Business Acquisition, Pro Forma Net Income (Loss)	$90,821	$64,769

Intangible_Assets_and_Goodwill2

Intangible Assets and Goodwill (Details) (USD $)	12 Months Ended
	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]	'
Finite-Lived Intangible Assets, Gross	$19,042,000
Finite-Lived Intangible Assets, Accumulated Amortization	296,000
Finite-Lived Intangible Assets, Net	18,746,000
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	2,400,000
Finite-Lived Intangible Assets, Amortization Expense, Year Two	2,400,000
Finite-Lived Intangible Assets, Amortization Expense, Year Three	1,900,000
Finite-Lived Intangible Assets, Amortization Expense, Year Four	1,900,000
Finite-Lived Intangible Assets, Amortization Expense, Year Five	1,900,000
Customer Relationships [Member]	'
Finite-Lived Intangible Assets [Line Items]	'
Finite-Lived Intangible Asset, Useful Life	'20 years
Finite-Lived Intangible Assets, Gross	7,600,000
Finite-Lived Intangible Assets, Accumulated Amortization	48,000
Finite-Lived Intangible Assets, Net	7,552,000
Real Estate [Member]	'
Finite-Lived Intangible Assets [Line Items]	'
Finite-Lived Intangible Asset, Useful Life	'2 years 2 months 12 days
Finite-Lived Intangible Assets, Gross	942,000
Finite-Lived Intangible Assets, Accumulated Amortization	55,000
Finite-Lived Intangible Assets, Net	887,000
Noncompete Agreements [Member]	'
Finite-Lived Intangible Assets [Line Items]	'
Finite-Lived Intangible Asset, Useful Life	'10 years
Finite-Lived Intangible Assets, Gross	3,100,000
Finite-Lived Intangible Assets, Accumulated Amortization	39,000
Finite-Lived Intangible Assets, Net	3,061,000
Trade Names [Member]	'
Finite-Lived Intangible Assets [Line Items]	'
Finite-Lived Intangible Asset, Useful Life	'6 years
Finite-Lived Intangible Assets, Gross	7,400,000
Finite-Lived Intangible Assets, Accumulated Amortization	154,000
Finite-Lived Intangible Assets, Net	$7,246,000

Intangible_Assets_and_Goodwill3

Intangible Assets and Goodwill Changes carrying amount of goodwill (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2011
Intangible Assets and Goodwill [Abstract]	'	'
Goodwill, Beginning balance	$4,815	$4,815
Goodwill, Acquired During Period	93,871	'
Goodwill, Ending Balance	$98,686	$4,815

Line_of_Credit_and_Long_Term_D2

Line of Credit and Long Term Debt (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Nov. 01, 2016	Nov. 01, 2015	Nov. 01, 2014
Debt Instrument [Line Items]	'	'	'	'
Long-term Line of Credit	$75,000,000	'	'	'
Debt Instrument, Interest Rate, Stated Percentage	0.79%	'	'	'
Line of Credit Facility, Maximum Borrowing Capacity	250,000,000	175,000,000	200,000,000	225,000,000
Debt Instrument, Covenant, Leverage Ratio	2	'	'	'
Debt Covenant, Minimum Net Income Requirement	1	'	'	'
Long-term Debt	75,000,000	'	'	'
Line of Credit Facility, Remaining Borrowing Capacity	169,500,000	'	'	'
Debt Instrument, Covenant Description	200,000,000	'	'	'
Line of Credit Facility, Amount Outstanding	$5,500,000	'	'	'
London Interbank Offered Rate (LIBOR) [Member]	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'
Debt Instrument, Basis Spread on Variable Rate	0.63%	'	'	'
Prime Rate [Member]	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'
Debt Instrument, Basis Spread on Variable Rate	0.00%	'	'	'

Accident_and_Workers_Compensat1

Accident and Workers' Compensation Insurance Liabilities (Details) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Accident and Workers' Compensation Insurance Liabilities [Line Items]	'
Auto liability retention limit	$2
Excess Insurance Coverage Limit	75
Workers compensation retention limit	1
Trust fund requirements	0.7
Restricted Cash and Cash Equivalents, Noncurrent	10.5
Letters of Credit Outstanding, Amount	8.7
Gordon Trucking Company, Inc [Member]	'
Accident and Workers' Compensation Insurance Liabilities [Line Items]	'
Auto liability retention limit	0.5
Excess Insurance Coverage Limit	75
Workers compensation retention limit	0.5
Trust fund requirements	0.7
Restricted Cash and Cash Equivalents, Noncurrent	$0.60

Income_Taxes_Details

Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Taxes [Abstract]	'	'	'
PortionOfTaxBenefitRecordedPositionsMoreLikelyThanNotToBeSustained	50.00%	'	'
Income Tax Uncertainties [Abstract]	'	'	'
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$8,600,000	$10,100,000	'
Unrecognized Tax Benefits, Period Increase (Decrease)	-2,300,000	-300,000	'
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	6,700,000	7,400,000	'
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	700,000	600,000	1,200,000
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Lower Bound	-400,000	'	'
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Upper Bound	1,400,000	'	'
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]	'	'	'
Balance beginning of period	15,723,000	16,062,000	'
Additions based on tax positions related to current year	843,000	1,146,000	'
Additions for tax positions of prior years	616,000	1,075,000	'
Reductions for tax positions of prior years	-300,000	-134,000	'
Reductions due to lapse of applicable statute of limitations	-1,984,000	-2,426,000	'
Settlements	-1,466,000	0	'
Balance end of period	13,432,000	15,723,000	16,062,000
Valuation Allowance [Abstract]	'	'	'
Valuation Allowance, Amount	$0	$449,000	'

Income_Taxes_Income_Tax_Rate_R

Income Taxes Income Tax Rate Reconciliation (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Taxes [Abstract]	'	'	'
Income Tax Reconciliation, Income Tax Expense (Benefit), at Federal Statutory Income Tax Rate	$39,395	$33,451	$37,565
Income Tax Reconciliation, State and Local Income Taxes	3,242	1,554	981
Income Tax Reconciliation, Tax Exempt Income	-20	-48	104
Income Tax Reconciliation, Tax Contingencies	-766	-616	-1,159
Income Tax Reconciliation, Other Adjustments	123	-307	115
Income Tax Expense (Benefit)	$41,974	$34,034	$37,398

Income_Taxes_Income_Tax_Expens

Income Taxes Income Tax Expense Detail (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Taxes [Abstract]	'	'	'
Current Federal Tax Expense (Benefit)	$30,560	$38,148	$20,460
Current State and Local Tax Expense (Benefit)	1,152	1,636	2,195
Current Income Tax Expense (Benefit)	31,712	39,784	22,655
Deferred Federal Income Tax Expense (Benefit)	7,192	-5,890	16,587
Deferred State and Local Income Tax Expense (Benefit)	3,070	140	-1,844
Deferred Income Tax Expense (Benefit)	10,262	-5,750	14,743
Income Tax Expense (Benefit)	$41,974	$34,034	$37,398

Income_Taxes_Deferred_Tax_Summ

Income Taxes Deferred Tax Summary (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Income Taxes [Abstract]	'	'
Net deferred tax assets	$14,177	$13,797
Deferred Tax Liabilities, Noncurrent	-61,948	-51,306
Deferred Tax Assets (Liabilities), Net	($47,771)	($37,509)

Income_Taxes_Deferred_tax_asse

Income Taxes Deferred tax assets and liabilties (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Income Taxes [Abstract]	'	'
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts	$291	$305
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities	6,980	6,655
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost	648	579
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Self Insurance	26,000	27,549
Deferred Tax Assets, Unrealized Losses on Available-for-Sale Securities, Gross	0	449
Deferred Tax Assets, Tax Deferred Expense	4,846	5,658
Deferred Tax Assets, Other	1,889	1,011
Deferred Tax Assets, Gross	40,654	42,206
Deferred Tax Assets, Valuation Allowance	0	-449
Deferred Tax Assets, Net	40,654	41,757
Deferred Tax Liabilities, Property, Plant and Equipment	-85,849	-77,177
Deferred Tax Liabilities, Goodwill and Intangible Assets	-1,835	-1,351
Deferred Tax Liabilities, Deferred Expense	-741	-738
Deferred Income Tax Liabilities	-88,425	-79,266
Deferred Tax Assets (Liabilities), Net	($47,771)	($37,509)

Operating_Leases_Operating_Lea2

Operating Leases Operating Leases (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Operating Leased Assets [Line Items]	'	'
Operating Leases, Future Minimum Payments Due, Next Twelve Months	$11,249,000	'
Operating Leases, Future Minimum Payments, Due in Two Years	7,156,000	'
Operating Leases, Future Minimum Payments, Due in Three Years	5,401,000	'
Operating Leases, Future Minimum Payments, Due in Four Years	4,109,000	'
Operating Leases, Future Minimum Payments, Due in Five Years	3,424,000	'
Operating Leases, Future Minimum Payments, Due Thereafter	0	'
Operating Leases, Future Minimum Payments Due	31,339,000	'
Operating Leases, Rent Expense	1,300,000	0
Related Party [Member]	'	'
Operating Leased Assets [Line Items]	'	'
Operating Leases, Future Minimum Payments Due, Next Twelve Months	9,853,000	'
Operating Leases, Future Minimum Payments, Due in Two Years	6,972,000	'
Operating Leases, Future Minimum Payments, Due in Three Years	5,401,000	'
Operating Leases, Future Minimum Payments, Due in Four Years	4,109,000	'
Operating Leases, Future Minimum Payments, Due in Five Years	3,424,000	'
Operating Leases, Future Minimum Payments, Due Thereafter	0	'
Operating Leases, Future Minimum Payments Due	29,759,000	'
Operating Leases, Rent Expense	930,000	'
Equipment Leased to Other Party [Member]	'	'
Operating Leased Assets [Line Items]	'	'
Operating Leases, Future Minimum Payments Due, Next Twelve Months	1,396,000	'
Operating Leases, Future Minimum Payments, Due in Two Years	184,000	'
Operating Leases, Future Minimum Payments, Due in Three Years	0	'
Operating Leases, Future Minimum Payments, Due in Four Years	0	'
Operating Leases, Future Minimum Payments, Due in Five Years	0	'
Operating Leases, Future Minimum Payments, Due Thereafter	0	'
Operating Leases, Future Minimum Payments Due	1,580,000	'
Terminal Facilities [Member]	'	'
Operating Leased Assets [Line Items]	'	'
Operating Leases, Rent Expense	700,000	'
Terminal Facilities [Member] | Related Party [Member]	'	'
Operating Leased Assets [Line Items]	'	'
Operating Leases, Rent Expense	572,000	'
Gordon Trucking Company, Inc [Member]	'	'
Operating Leased Assets [Line Items]	'	'
Operating Leases, Rent Expense	'	$0

Stockholders_Equity_Details

Stockholders' Equity (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Feb. 10, 2012	Sep. 30, 2001
Share Repurchases [Abstract]	'	'	'	'	'
Stock Repurchase Shares Authorized	3,225	'	'	5,000	15,400
Share repurchase authorization increase	'	3,225	'	2,757	'
Treasury Stock, Shares, Acquired	0	1,775	4,214	'	'
Repurchases of Common Stock	$0	$24,190	$56,350	'	'

Stockholders_Equity_Dividends_

Stockholders' Equity Dividends Paid (Details) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stockholders' Equity Attributable to Parent [Abstract]	'	'	'	'
Payments of Dividends	$85	$6.90	$6.90	$7.10

StockBased_Compensation_Detail

Stock-Based Compensation (Details) (USD $)	12 Months Ended			54 Months Ended		6 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	31-May-16	Jul. 11, 2011	Dec. 31, 2013	Dec. 31, 2013
						Maximum [Member]	Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'	'
weighted average fair value price of stock awards lower	'	'	'	'	'	'	$13.86
weighted average fair value price of stock awards upper	'	'	'	'	'	$18.18	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value	$1,100,000	$1,000,000	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$13.57	$13.57	$0	'	'	'	'
Stock-based Compensation	1,184,000	2,379,000	150,000	5,200,000	'	'	'
Restricted Stock Shares Authorized	'	'	'	'	900,000	'	'
Stock Issued During Period, Shares, Restricted Stock Award, Gross	'	351,000	'	'	'	'	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$1,200,000	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$13.81	$13.57	$13.57	'	'	'	'
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)	277,000	351,000	0	'	'	'	'
Unvested at beginning of year, Weighted Average Grant Date Fair Value (in dollars)	$13.57	$13.57	$0	$13.57	'	'	'
Share-based Compensation Arrangements by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	23,000	0	351,000	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$17.28	$0	$13.57	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	-75,000	-70,000	0	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$14.04	$13.57	$0	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	-13,000	-4,000	0	'	'	'	'
Outstanding (unvested) at end of year, Number of Restricted Stock Awards (in shares)	211,500	277,000	351,000	'	'	'	'
Outstanding (unvested) at end of year, Weighted Average Grant Date Fair Value (in dollars)	$13.81	$13.57	$13.57	'	'	'	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition (in years)	'	'1 year 9 months 22 days	'	'4 years 5 months 15 days	'	'	'

Profit_Sharing_Plan_and_Retire1

Profit Sharing Plan and Retirement Plan (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Profit Sharing Plan and Retirement Plan [Abstract]	'	'	'
Defined Contribution Plan, Cost Recognized	$0.40	$0.70	$0.80

Related_Party_Details

Related Party (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Related Party Transaction [Line Items]	'	'	'
Due to Related Parties, Current	$1,300,000	'	'
Proceeds from sale of property and equipment	92,313,000	29,184,000	73,018,000
Operating Leases, Rent Expense	1,300,000	0	'
Related Party Transaction, Expenses from Transactions with Related Party	7,208,000	'	'
Related Party [Member]	'	'	'
Related Party Transaction [Line Items]	'	'	'
Payments for tractor purchase	6,884,000	'	'
Proceeds from sale of property and equipment	-2,138,000	'	'
Payments for parts and services	1,058,000	'	'
Operating Leases, Rent Expense	930,000	'	'
Administrative Services Revenue	-98,000	'	'
Terminal Facilities [Member]	'	'	'
Related Party Transaction [Line Items]	'	'	'
Operating Leases, Rent Expense	700,000	'	'
Terminal Facilities [Member] | Related Party [Member]	'	'	'
Related Party Transaction [Line Items]	'	'	'
Operating Leases, Rent Expense	572,000	'	'
Related Party Transaction, Expenses from Transactions with Related Party	$600,000	'	'

Commitments_and_Contingencies_

Commitments and Contingencies (Details) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]	'
Unrecorded Unconditional Purchase Obligation	$79.50

Quarterly_Financial_Informatio2

Quarterly Financial Information (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Information (Unaudited) [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Operating Revenue	$183,348	$130,645	$133,992	$134,273	$136,192	$135,010	$139,710	$134,833	$582,257	$545,745	$528,623
Operating Income (Loss)	26,720	26,000	29,375	30,207	24,708	19,667	26,748	23,778	112,302	94,901	106,557
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	26,596	26,126	29,504	30,330	24,882	19,858	26,915	23,920	112,556	95,575	107,330
Net income	$15,842	$15,868	$19,138	$19,734	$14,292	$12,434	$18,227	$16,588	$70,582	$61,541	$69,932
Basic EPS	$0.18	$0.19	$0.23	$0.23	$0.17	$0.15	$0.21	$0.19	$0.83	$0.72	$0.78
Diluted EPS	$0.18	$0.19	$0.23	$0.23	$0.17	$0.14	$0.21	$0.19	$0.83	$0.71	$0.78

Schedule_II_Valuation_of_Quali1

Schedule II Valuation of Qualifying Accounts and Reserves (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Movement in Valuation Allowances and Reserves [Roll Forward]	'	'	'
Valuation Allowances and Reserves, Balance Beginning of Period	$829	$791	$775
Valuation Allowances and Reserves, Charged to Cost and Expense	-27	205	83
Valuation Allowances and Reserves, Charged to Other Accounts	238	0	0
Valuation Allowances and Reserves, Deductions	12	167	67
Valuation Allowances and Reserves, Balance End of Period	$1,028	$829	$791