Knight Transportation 10-K 28 Feb 14 2013 FY Annual report Financial data

Document_And_Entity_Informatio

Document And Entity Information (USD $)	12 Months Ended
	Dec. 31, 2013	Feb. 26, 2014	Jun. 28, 2013
Document and Entity Information [Abstract]	'	'	'
Entity Registrant Name	'Knight Transportation Inc	'	'
Document Type	'10-K	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Common Stock, Shares Outstanding	'	80,642,850	'
Entity Public Float	'	'	$1,000,000,000
Amendment Flag	'false	'	'
Entity Central Index Key	'0000929452	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Document Period End Date	31-Dec-13	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current Assets:	'	'
Cash and cash equivalents	$992	$5,684
Trade receivables, net of allowance for doubtful accounts of $2,409 and $1,917, respectively	116,391	102,553
Notes receivable, net of allowance for doubtful notes receivable of $312 and $291, respectively	774	791
Related party notes and interest receivable	748	2,814
Prepaid expenses	15,026	17,035
Assets held for sale	16,476	18,362
Other current assets	11,066	12,449
Current deferred tax assets	3,359	3,409
Total current assets	164,832	163,097
Property and Equipment:	'	'
Revenue equipment	683,275	681,864
Land and land improvements	45,615	38,979
Buildings and building improvements	115,201	100,158
Furniture and fixtures	18,605	15,953
Shop and service equipment	9,564	9,065
Leasehold improvements	3,382	2,989
	875,642	849,008
Less: accumulated depreciation and amortization	-283,851	-264,944
Property and equipment, net	591,791	584,064
Notes receivable, long-term	4,047	3,692
Goodwill	10,257	10,276
Other long-term assets and restricted cash and investments	36,194	21,383
Total long-term assets	642,289	619,415
Total assets	807,121	782,512
Current Liabilities:	'	'
Accounts payable	14,354	11,281
Accrued payroll and purchased transportation	13,864	10,489
Accrued liabilities	18,800	16,020
Claims accrual – current portion	15,616	15,892
Dividend payable – current portion	168	141
Total current liabilities	62,802	53,823
Long-term Liabilities:	'	'
Claims accrual – long-term portion	8,889	10,340
Long-term dividend payable and other liabilities	2,486	2,638
Deferred tax liabilities	142,504	144,871
Long-term debt	38,000	80,000
Total long-term liabilities	191,879	237,849
Total liabilities	254,681	291,672
Commitments and Contingencies (Note 5)	'	'
Shareholders' Equity:	'	'
Preferred stock, $0.01 par value; 50,000 shares authorized; none issued	0	0
Common stock, $0.01 par value; 300,000 shares authorized; 80,199 and 79,760 shares issued and outstanding at December 31, 2013 and 2012, respectively	802	798
Additional paid-in capital	150,079	142,837
Accumulated other comprehensive income (loss)	4,582	-302
Retained earnings	396,032	346,899
Total Knight Transportation shareholders' equity	551,495	490,232
Noncontrolling interest	945	608
Total shareholders' equity	552,440	490,840
Total liabilities and shareholders' equity	$807,121	$782,512

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parentheticals) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, except Per Share data, unless otherwise specified
Allowance for doubtful accounts (in Dollars)	$2,409	$1,917
Allowance for doubtful notes receivable (in Dollars)	$312	$291
Preferred stock, par value (in Dollars per share)	$0.01	$0.01
Preferred stock, shares authorized	50,000	50,000
Preferred stock, issued	0	0
Common stock, par value (in Dollars per share)	$0.01	$0.01
Common stock, shares authorized	300,000	300,000
Common stock, shares issued	80,199	79,760
Common stock, shares outstanding	80,199	79,760

Consolidated_Statements_of_Inc

Consolidated Statements of Income (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue:	'	'	'
Revenue, before fuel surcharge	$791,851	$752,151	$697,286
Fuel surcharge	177,386	183,885	168,913
Total revenue	969,237	936,036	866,199
Operating Expenses:	'	'	'
Salaries, wages and benefits	234,306	238,266	218,686
Fuel	214,843	230,178	226,471
Operations and maintenance	64,715	61,875	53,714
Insurance and claims	29,350	32,138	30,072
Operating taxes and licenses	15,624	16,184	15,212
Communications	5,015	5,172	5,534
Depreciation and amortization	86,129	85,056	75,832
Purchased transportation	189,667	148,022	129,143
Miscellaneous operating expenses	15,679	10,878	11,514
Total operating expenses	855,328	827,769	766,178
Income from operations	113,909	108,267	100,021
Other Income (Expense):	'	'	'
Interest income	413	417	1,068
Interest expense	-462	-457	-180
Other income	2,844	1,550	279
Total other income	2,795	1,510	1,167
Income before income taxes	116,704	109,777	101,188
Income Taxes	46,680	45,014	40,480
Net income	70,024	64,763	60,708
Net income attributable to noncontrolling interest	-742	-646	-460
Net income attributable to Knight Transportation	$69,282	$64,117	$60,248
Basic Earnings Per Share (in Dollars per share)	$0.87	$0.80	$0.74
Diluted Earnings Per Share (in Dollars per share)	$0.86	$0.80	$0.74
Weighted Average Shares Outstanding - Basic (in Shares)	79,994	79,673	81,439
Weighted Average Shares Outstanding - Diluted (in Shares)	80,330	80,000	81,872

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net income attributable to Knight Transportation	$69,282	$64,117	$60,248
Other comprehensive income, net of tax:	'	'	'
Unrealized gain/(loss) from available-for-sale securities	4,884	146	-455
Comprehensive income	$74,166	$64,263	$59,793

Consolidated_Statements_of_Sha

Consolidated Statements of Shareholders' Equity (USD $)	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Parent [Member]	Noncontrolling Interest [Member]	Total
In Thousands, except Share data
Balance at Dec. 31, 2010	$837	$126,975	$379,714	$7	$507,533	($69)	$507,464
Balance (in Shares) at Dec. 31, 2010	83,693,000	'	'	'	'	'	'
Exercise of stock options and RSU’s	3	2,006	'	'	2,009	'	2,009
Exercise of stock options and RSU’s (in Shares)	275,000	'	'	'	'	'	189,788
Issuance of common stock	'	112	'	'	112	'	112
Issuance of common stock (in Shares)	6,000	'	'	'	'	'	'
Stock repurchases	-46	'	-76,518	'	-76,564	'	-76,564
Stock repurchases (in Shares)	-4,582,000	'	'	'	'	'	'
Shares withheld from RSU settlement	'	'	-513	'	-513	'	-513
Excess tax benefit of stock option exercises	'	129	'	'	129	'	129
Employee stock-based compensation expense	'	3,501	'	'	3,501	'	3,501
Cash dividends paid and dividends accrued	'	'	-19,641	'	-19,641	'	-19,641
Net income attributable to Knight	'	'	60,248	'	60,248	'	60,248
Other comprehensive income (loss)	'	'	'	-455	-455	'	-455
Distribution to noncontroling interest	'	'	'	'	'	'	0
Net income (loss) attributable to noncontrolling interest	'	'	'	'	'	460	460
Balance at Dec. 31, 2011	794	132,723	343,290	-448	476,359	391	476,750
Balance (in Shares) at Dec. 31, 2011	79,392,000	'	'	'	'	'	'
Exercise of stock options and RSU’s	4	3,619	'	'	3,623	'	3,623
Exercise of stock options and RSU’s (in Shares)	359,000	'	'	'	'	'	281,993
Issuance of common stock	'	148	'	'	148	'	148
Issuance of common stock (in Shares)	9,000	'	'	'	'	'	'
Shares withheld from RSU settlement	'	'	-650	'	-650	'	-650
Excess tax benefit of stock option exercises	'	30	'	'	30	'	30
Employee stock-based compensation expense	'	6,317	'	'	6,317	'	6,317
Cash dividends paid and dividends accrued	'	'	-59,858	'	-59,858	'	-59,858
Net income attributable to Knight	'	'	64,117	'	64,117	'	64,117
Other comprehensive income (loss)	'	'	'	146	146	'	146
Distribution to noncontroling interest	'	'	'	'	'	-429	-429
Net income (loss) attributable to noncontrolling interest	'	'	'	'	'	646	646
Balance at Dec. 31, 2012	798	142,837	346,899	-302	490,232	608	490,840
Balance (in Shares) at Dec. 31, 2012	79,760,000	'	'	'	'	'	'
Exercise of stock options and RSU’s	4	4,341	'	'	4,345	'	4,345
Exercise of stock options and RSU’s (in Shares)	429,000	'	'	'	'	'	345,302
Issuance of common stock	'	167	'	'	167	'	167
Issuance of common stock (in Shares)	10,000	'	'	'	'	'	'
Shares withheld from RSU settlement	'	'	-739	'	-739	'	-739
Excess tax benefit of stock option exercises	'	-81	'	'	-81	'	-81
Employee stock-based compensation expense	'	2,815	'	'	2,815	'	2,815
Cash dividends paid and dividends accrued	'	'	-19,410	'	-19,410	'	-19,410
Net income attributable to Knight	'	'	69,282	'	69,282	'	69,282
Other comprehensive income (loss)	'	'	'	4,884	4,884	'	4,884
Distribution to noncontroling interest	'	'	'	'	'	-405	-405
Net income (loss) attributable to noncontrolling interest	'	'	'	'	'	742	742
Balance at Dec. 31, 2013	$802	$150,079	$396,032	$4,582	$551,495	$945	$552,440
Balance (in Shares) at Dec. 31, 2013	80,199,000	'	'	'	'	'	'

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash Flows From Operating Activities:	'	'	'
Net income	$70,024,000	$64,763,000	$60,708,000
Adjustments to reconcile net income to net cash provided by operating activities	'	'	'
Depreciation and amortization	86,129,000	85,056,000	75,832,000
Gain on sale of equipment	-7,550,000	-8,916,000	-6,865,000
Earn-out on sold investment	-467,000	-216,000	-115,000
Gain on sale of available-for-sale securities	-1,925,000	-61,000	-90,000
Gain from investment in Transportation Resource Partners III	-669,000	-261,000	-74,000
Impairment of investment in Transportation Resource Partners	209,000	0	'
Compensation expense for issuance of common stock to certain members of board of directors	167,000	148,000	112,000
Provision for allowance for doubtful accounts and notes receivable	1,008,000	883,000	578,000
Deferred income taxes	-5,338,000	-1,975,000	30,412,000
Excess tax benefits related to stock-based compensation	'	-30,000	-60,000
Stock-based compensation expense	2,815,000	6,317,000	3,501,000
Changes in operating assets and liabilities:	'	'	'
Short-term investments held for trading	'	'	24,379,000
Trade receivables	-14,828,000	-2,167,000	-22,955,000
Related party interest receivable	'	'	-49,000
Other current assets	1,384,000	-2,844,000	-4,888,000
Prepaid expenses	2,008,000	-6,904,000	-1,618,000
Income tax receivable	'	3,821,000	3,092,000
Other long-term assets	-390,000	81,000	-462,000
Accounts payable	2,424,000	4,783,000	-3,034,000
Accrued liabilities and claims accrual	3,517,000	8,342,000	2,293,000
Net cash provided by operating activities	138,518,000	150,820,000	160,697,000
Cash Flows From Investing Activities:	'	'	'
Purchases of property and equipment	-140,612,000	-160,633,000	-172,916,000
Proceeds from sale of equipment/assets held for sale	55,244,000	39,789,000	34,608,000
Purchase of long-term available-for-sale securities	-10,035,000	-2,033,000	-313,000
Cash proceeds from sale of available-for-sale securities	8,782,000	112,000	440,000
Cash receipt from notes receivable	2,383,000	1,856,000	2,674,000
Cash payment for notes receivable	-646,000	-366,000	-1,951,000
Cash proceeds from related party notes receivable	1,570,000	54,000	219,000
Contributions to Transportation Resource Partners	-3,201,000	-2,382,000	-2,316,000
Return of investment in Transportation Resource Partners	467,000	216,000	115,000
Change in restricted cash and investments	343,000	-416,000	-651,000
Net cash used in investing activities	-85,705,000	-123,803,000	-140,091,000
Cash Flows From Financing Activities:	'	'	'
Dividends paid	-19,445,000	-59,141,000	-19,540,000
Payments to repurchase company stock	'	'	-76,564,000
Excess tax benefits related to stock-based compensation	'	30,000	60,000
Payments of proceeds from borrowing on line of credit	-42,000,000	25,000,000	55,000,000
Cash distribution to noncontrolling interest holder	-405,000	-429,000	0
Proceeds from exercise of stock options	4,345,000	3,623,000	2,009,000
Net cash used in financing activities	-57,505,000	-30,917,000	-39,035,000
Net decrease in Cash and Cash Equivalents	-4,692,000	-3,900,000	-18,429,000
Cash and Cash Equivalents, beginning of year	5,684,000	9,584,000	28,013,000
Cash and Cash Equivalents, end of year	992,000	5,684,000	9,584,000
Non-cash investing and financing transactions:	'	'	'
Equipment acquired included in accounts payable	2,892,000	2,206,000	10,029,000
Dividend accrued for restricted stock units	2,216,000	2,251,000	1,534,000
Transfer from property and equipment to assets held for sale	40,422,000	34,244,000	35,540,000
Financing provided to independent contractors for equipment sold	1,731,000	1,200,000	2,359,000
Cash flow information:	'	'	'
Income taxes paid	51,904,000	40,422,000	6,828,000
Interest expense paid	$450,000	$475,000	$154,000

Note_1_Organization_and_Summar

Note 1 - Organization and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Significant Accounting Policies [Text Block]	'
	1.     Organization and Summary of Significant Accounting Policies
	a.     Nature of Business
	Knight Transportation, Inc. (an Arizona corporation) and subsidiaries (the "Company") is a short to medium-haul truckload carrier of general commodities and transportation logistics services provider headquartered in Phoenix, Arizona. The Company also has service centers located throughout the United States. The Company has two reportable segments, Asset-Based and Non-Asset-Based. The Asset-Based segment provides truckload carrier dry van, temperature-controlled (refrigerated), and drayage services, and the Non-Asset-Based segment provides logistics, freight management, brokerage, rail intermodal, and other non-trucking services. The Company is subject to regulation by the U.S. Department of Transportation, U.S. Environmental Protection Agency, U.S. Department of Homeland Security, and various state regulatory authorities.
	b.     Significant Accounting Policies
	Principles of Consolidation - The accompanying consolidated financial statements include Knight Transportation, Inc. and its wholly owned and controlled subsidiaries. The Company's non-controlling interests in subsidiaries are not significant. All intercompany accounts and transactions are eliminated upon consolidation.
	Use of Estimates - The preparation of financial statements in conformity with United States 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 consolidated financial statements. Estimates and assumptions equally apply to the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
	Cash and Cash Equivalents - Cash and cash equivalents are comprised of cash, money market funds, and short-term, highly liquid instruments with insignificant interest rate risk and original maturities of three months or less. Cash balances with institutions may be in excess of Federal Deposit Insurance Corporation ("FDIC") limits or may be invested in sweep accounts that are not insured by the institution, the FDIC or any other government agency.
	Notes Receivable – The Company provides financing to independent contractors and third parties on equipment sold or leased under the Company's equipment sale program. Most of the notes are collateralized and are due in weekly installments, including principal and interest payments, ranging from 2.0% to 20%. The Company had 117 and 126 loans outstanding from independent contractors and third parties as of December 31, 2013 and 2012, respectively.
	The notes receivable balances are classified separately between current and long-term notes in the consolidated balance sheets. The current and long-term balances of our notes receivables as of December 31, 2013 and 2012 are as follows:
		2013			2012
		(In thousands)
	Notes receivable from independent contractors	$	503		$	605
	Notes receivable from third parties		4,630			4,169
	Gross notes receivable		5,133			4,774
	Allowance for doubtful notes receivable		(312	)		(291	)
	Total notes receivable, net of allowance	$	4,821		$	4,483
	Current portion, net of allowance		774			791
	Long-term portion	$	4,047		$	3,692
	Assets Held for Sale - The Company had $16.5 million and $18.4 million of revenue equipment not being utilized in operations, which is classified as assets held for sale, as of December 31, 2013 and 2012, respectively. Assets held for sale are recorded at the lower of depreciated value or fair market value less selling costs and are not subject to depreciation. The Company periodically reviews the carrying value of these assets for possible impairment. No impairment was recorded in 2013 or 2012. The Company expects to sell these assets within 12 months.
	Other Current Assets - Included in other current assets are inventories of tires, spare parts, and fuel.
	Property and Equipment - Property and equipment is stated at cost less accumulated depreciation. Property and equipment is depreciated to estimated salvage values using the straight-line method of depreciation over the following estimated useful lives:
		Years
	Land improvements	5	-	10
	Buildings and improvements	15	-	30
	Furniture and fixtures	3	-	10
	Shop and service equipment	2	-	5
	Revenue equipment	5	-	10
	Leasehold improvements	1	-	5
	The Company expenses repairs and maintenance as incurred. For the years ended December 31, 2013, 2012, and 2011, repairs and maintenance expense totaled approximately $30.5 million, $30.4 million, and $24.2 million, respectively. The expense is included in operations and maintenance expense in the accompanying consolidated statements of income.
	The Company periodically reviews the reasonableness of its estimates regarding useful lives and salvage values for revenue equipment and other long-lived assets based upon, among other things, the Company's experience with similar assets, conditions in the used revenue equipment market, and prevailing industry practice.
	Tires on revenue equipment purchased are capitalized as a part of the equipment cost and depreciated over the life of the vehicle. Replacement tires and recapping costs are expensed when placed in service.
	Other Long-term Assets and Restricted Cash and Investments include:
		2013			2012
		(In thousands)
	Investment in Transportation Resource Partners (TRP)	$	2,035		$	2,246
	Investment in Transportation Resource Partners III (TRP III)		11,440			7,568
	Restricted Cash and Investments		3,603			3,947
	Available-For-Sale Equity Securities		17,454			6,369
	Other		1,662			1,253
		$	36,194		$	21,383
	In 2003, the Company signed a partnership agreement with TRP, a company that makes privately negotiated equity investments. According to the original partnership agreement, the Company committed to invest $5.0 million out of approximately $260.0 million total, for a 1.9% ownership interest. In early 2006, the Company increased the commitment amount to $5.5 million. Contributions to TRP are accounted for using the cost method as the level of influence over the operations of TRP is minor. The Company contributed $142,000 to TRP as an additional investment in 2011, and no additional contributions were made in 2012 or 2013. The Company received additional earn-outs of $467,000, $216,000, and $115,000 in 2013, 2012, and 2011, respectively, for disposed portfolios. The earn-outs are recognized as gains in the year received. The Company also recorded a $209,000 impairment in 2013 for an other-than-temporary loss in its investment, resulting from unrealized losses on the investments remaining within the TRP portfolio. The Company's ownership interest in TRP is approximately 1.9%, with a carrying value of $2.0 million and $2.2 million at December 31, 2013 and 2012, respectively.
	In the fourth quarter of 2008, the Company committed to invest $15.0 million in a new partnership managed and operated by the managers and principals of TRP. The new partnership, TRP III, focuses on the same investment opportunities as TRP. Since its inception, the Company has contributed approximately $10.8 million to TRP III, leaving an outstanding commitment of $4.2 million as of December 31, 2013. The investment in TRP III is accounted for using the equity method. The Company has recorded income of approximately $669,000, $261,000, and $74,000 for its investment in TRP III for years ended December 31, 2013, 2012, and 2011, respectively. At December 31, 2013, the investment balance in TRP III was $11.4 million, compared to $7.6 million at December 31, 2012. The Company's ownership interest was approximately 6.1% as at December 31, 2013.
	Restricted Cash and Investments – In connection with the Company's self-insurance program, $3.6 million and $3.9 million have been set aside in escrow accounts to meet statutory requirements as of December 31, 2013 and 2012, respectively.
	In accordance with the provisions of ASC 210, Balance Sheet, and ASC 320, Investments – Debt and Equity Securities, the Company's investments in debt or equity securities are classified as either trading securities, held-to-maturity securities, or available-for-sale securities, based on the Company's intent with respect to those securities. Investments in debt and equity securities are classified as trading securities if they are held principally for the purpose of selling in the near term. Investments in debt securities are classified as held-to-maturity if the Company has the positive intent to hold such securities to maturity and the ability to do so. Investments in debt and equity securities not classified as trading or held-to-maturity are classified as available-for-sale.
	Impairment of Long-Lived Assets – ASC 360-10, Property, Plant and Equipment, provides a single accounting model for the assessment of impairment of long-lived assets. In accordance with ASC 360-10, Long-lived Assets, such as property and equipment and purchased intangibles to be held and used in operations, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Long-lived assets are grouped at the lowest level at which identifiable cash flows are largely independent when assessing impairment. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated future cash flows, an impairment charge is recognized by the amount by which the carrying amount of the asset exceeds the fair value of the asset. Assets classified as held for sale are not depreciated and are presented in the Company's consolidated balance sheets at the lower of the carrying amount or fair value less costs to sell. Revenue equipment classified as held for sale is presented in "assets held for sale" on the Company's consolidated balance sheets. Recoverability of long-lived assets is dependent upon, among other things, the Company's ability to continue to achieve profitability in order to meet its obligations when they become due. In the opinion of management, based upon current information, the carrying amount of long-lived assets will be recovered by future cash flows generated through the use of such assets over their respective estimated useful lives.
	Goodwill & Intangibles, net - Goodwill is not amortized, but it is reviewed for impairment at least annually (December 31), or more frequently should any of the circumstances listed in ASC 350-20, Goodwill, occur. The standard permits an entity to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not the fair value of a reporting unit is less than its carrying amount. If, after assessing the totality of events or circumstances, it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, then performing the two-step impairment test is unnecessary. However, if an entity concludes otherwise, then it is required to perform the impairment test as prescribed in ASC 350-20. Goodwill is required to be tested for impairment at the reporting unit level utilizing a two-step methodology. The initial step requires the Company to determine the fair value of the reporting unit and compare it to the carrying value of such unit, including goodwill. No impairment is recognized if the fair value exceeds the carrying value; however, if the carrying value of the reporting unit exceeds its fair value, the goodwill of the reporting unit may be impaired. The amount, if any, of the impairment would then be measured in the second step. The Company completed this annual test as of December 31, 2013, and no adjustment for impairment was determined to be necessary. The Company has no accumulated goodwill impairment loss from prior years.
	During fiscal year 2006, the Company recorded approximately $1.8 million of goodwill and $310,000 of finite lived intangible assets in connection with the acquisition of most of the trucking assets of Roads West. In 2007, the Company paid Roads West $135,000 for an earn-out, representing the final earn-out under the purchase agreement. The earn-out paid in 2007 was recorded as additional goodwill related to this acquisition. The basis of goodwill for tax purposes was determined to be in excess of the book basis of goodwill. Under this circumstance, ASC 740, Income Taxes, requires that the goodwill be separated into two components for the acquisitions before the adoption of ASC 805, Business Combination. The first component is equivalent to book goodwill, and future tax amortization of this component is treated as a temporary difference, for which a deferred tax liability is established. The second component is the excess tax goodwill over the book goodwill, for which no deferred taxes are recognized. The tax benefit from the recognition of the amortization of the second component on the tax return is treated as a reduction in the book basis of goodwill. The finite lived intangible portion was amortized using the straight-line method over a five-year period, and was fully amortized as of December 31, 2011.
	The changes in the carrying amounts of goodwill were as follows:
		2013			2012
		(In thousands)
	Goodwill at beginning of period	$	10,276		$	10,295
	Amortization relating to deferred tax assets		(19	)		(19	)
	Goodwill at end of period	$	10,257		$	10,276
	Claims Accrual - The claims reserves represent accruals for estimated pending claims within the self-insured retention ("SIR"), including adverse development of known claims and incurred but not reported claims. These estimates are based on the Company's claims experience, including claims settlement patterns, historical payment trends, the experience/knowledge of the Company's self-administered claims as well as that of the third-party administrator as it relates to workers' compensation claims, along with assumptions about future events. The most significant assumptions used in the estimation process include determining the trend in costs, the expected cost of claims incurred but not reported, and the expected costs to settle or pay outstanding claims. Changes in assumptions and changes in actual experience could cause these estimates to change significantly in the near term. A higher SIR may cause assumptions and estimates to vary more unpredictably than a lower SIR.
	Revenue Recognition - The Company recognizes revenue when persuasive evidence of an arrangement exists, delivery has occurred, the fee is fixed or determinable, and collectability is probable. These conditions are met upon delivery.
	In accordance with ASC 605-45, Revenue Recognition – Principal Agent Consideration, the Company accounts for revenue from our Asset-Based operations, our Non-Asset-Based operations, and revenue on freight transported by independent contractors on a gross basis. The Company is the primary obligor in the arrangements, the Company has the ability to establish prices, the Company has discretion in selecting the independent contractor or other third-party that will perform the service, the Company has the risk of loss in the event of cargo claims, and the Company bears credit risk with customer payments.  Accordingly, all such revenue billed to customers is classified as operating revenue and all corresponding payments to carriers for transportation services the Company arranges in connection with Brokerage and Intermodal activities and to independent contractor providers of revenue equipment are classified as purchased transportation expense.
	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 establishes an allowance for doubtful accounts based on historical experience and any known trends or uncertainties related to customer billing and account collectability. The Company reviews the adequacy of its allowance for doubtful accounts on a quarterly basis. Uncollectible accounts are written off when deemed uncollectible, and accounts receivable are presented net of an allowance for doubtful accounts. Historically, the Company has not had significant losses related to uncollectible accounts.
	Allowance for Doubtful Notes Receivable - The Company evaluates the collectability of notes and finance lease receivables on a customer-by-customer basis. The Company establishes an allowance for credit losses based on specific customer circumstances, payment patterns, credit risk changes, and historical loss experience. The Company reviews the adequacy of its allowance for doubtful notes receivable quarterly.  Uncollectible accounts are written off when deemed uncollectible, and notes receivable are presented net of an allowance for doubtful accounts. Historically, the Company has not had significant losses related to uncollectible accounts.
	Income Taxes - The Company accounts for income taxes under the asset and liability method. This method requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized as income in the period that includes the enactment date.
	The Company records a valuation allowance for deferred tax assets to the extent it believes these assets are not more likely than not to be realized. In making such determinations, the Company considers all available positive and negative evidence, including scheduled reversals of deferred tax liabilities, projected future taxable income, tax planning strategies, and recent financial operations. A valuation allowance for deferred tax assets has not been deemed necessary due to the Company's profitable operations.
	The Company recognizes a tax benefit from an uncertain tax position when it is more likely than not that the position will be sustained upon examination, including resolutions of any related appeals or litigation processes, based on the technical merits.
	Financial Instruments- The Company's financial instruments include cash equivalents, investments held for trading, available-for-sale securities, trade receivables, notes receivable, accounts payable, and long-term debt.  Due to the short-term nature of cash equivalents, trade receivables, and accounts payable, the fair value of these instruments approximates their recorded value.  Available-for-sale and trading securities consist of marketable equity and debt securities stated at fair value. Due to the variable interest rate, the fair value of long-term debt approximates fair value.
	Concentration of Credit Risk - Financial instruments that potentially subject the Company to credit risk consist principally of trade receivables and notes receivable. Revenue for the Company's three largest customers accounted for approximately 11%, 10% and 12% of the total revenue for the years ended 2013, 2012 and 2011, respectively. As of December 31, 2013, balances due from the three largest customers account for approximately 6.5% of the total trade receivable balance, compared to 7.7% as of December 31, 2012. Revenue from the Company's single largest customer represented approximately 4% of total revenue for the years ended December 31, 2013 and 2012, and approximately 5% for the year ended 2011. The balance due from the single largest customer accounts for approximately 1.2% of the total trade receivable balance as of December 31, 2013, compared to 1.3% as of December 31, 2012.
Earnings Per Share - A reconciliation of the numerator (net income) and denominator (weighted average number of shares outstanding) of the basic and diluted earnings per share ("EPS") computations for 2013, 2012, and 2011 are as follows (in thousands, except per share data):
	2013								2012						2011
	Net Income			Shares			Per Share		Net Income		Shares		Per Share		Net Income		Shares		Per Share
	(numerator)			(denominator)			Amount		(numerator)		(denominator)		Amount		(numerator)		(denominator)		Amount
Basic EPS	$	69,282			79,994		$	0.87	$	64,117		79,673	$	0.8	$	60,248		81,439	$	0.74
Effect of stock options & restricted stock		-			336					-		327				-		433
Diluted EPS	$	69,282			80,330		$	0.86	$	64,117		80,000	$	0.8	$	60,248		81,872	$	0.74
Certain shares of common stock were excluded in the computation of diluted earnings per share because the options' exercise prices were greater than the average market price of the common shares, and therefore, the effect would be anti-dilutive. A summary of those options for the twelve months ended December 31, 2013, 2012, and 2011, respectively, is as follows:
	2013			2012			2011
Number of anti-dilutive shares		1,917,020			1,926,298			2,655,814
New Accounting Pronouncements
In December 2013, the FASB issued ASU No. 2013-12, Definition of a Public Entity. This ASU intends to improve U.S. GAAP by providing a single definition of public business entity for use in future financial accounting and reporting guidance. The amended definition specifies that an entity that is required by the SEC to file or furnish financial statements with the SEC, or does file or furnish financial statements with the SEC, is considered a public business entity. The definition also addressed consolidated subsidiaries of public companies, stating that such an entity is not considered a public business entity for purposes of its stand-alone financial statements other than those included in an SEC filing by its parent or by other registrants or those that are issuers and are required to file or furnish financial statements with the SEC. There is no actual effective date for the amendment, however the term public business entity will be used in certain ASU's going forward.
In February 2013, the FASB issued ASU No. 2013-02, Other Comprehensive Income. This ASU intends to improve the reporting of reclassifications out of accumulated other comprehensive income by requiring an entity to report the effect of significant reclassifications out of accumulated other comprehensive income on the respective line items in net income if the amount being reclassified is required under GAAP to be reclassified in its entirety to net income. For other amounts that are not required under GAAP to be reclassified in their entirety to net income in the same reporting period, an entity is required to cross-reference other disclosures required under GAAP that provide additional detail about those amounts. The new guidance is effective for fiscal years beginning after December 15, 2012.  The amendments do not change the current requirements for reporting net income or other comprehensive income in financial statements and the adoption of this guidance did not have a material impact on the Company's consolidated financial statements.

Note_2_Fair_Value_Measurements

Note 2 - Fair Value Measurements	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Disclosures [Text Block]	'
	2.     Fair Value Measurements
	The Company's assets and liabilities that have been measured at fair value are based on principles set forth in ASC 820-10, Fair Value Measurements and Disclosure, for recurring and non-recurring fair value measurements of financial and non-financial assets and liabilities. This standard defines fair value, establishes a framework for measuring fair value in generally accepted accounting principles, and expands disclosures about fair value measurements. This standard establishes a three-level hierarchy for fair value measurements based upon the significant inputs used to determine fair value.  Observable inputs are those obtained from market participants external to the Company, while unobservable inputs are generally developed internally, utilizing management's estimates, assumptions, and specific knowledge of the nature of the assets or liabilities and related markets.  The three levels are defined as follows:
	Level 1 – Inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. An active market is defined as a market in which transactions for the assets or liabilities occur with sufficient frequency and volume to provide pricing information on an ongoing basis.
	Level 2 – Inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active (markets with few transactions), inputs other than quoted prices that are observable for the asset or liability (i.e., interest rates, yield curves, etc.) and inputs that are derived principally from or corroborated by observable market data correlation or other means (market corroborated inputs).
	Level 3 – Unobservable inputs, only used to the extent that observable inputs are not available, reflect the Company's assumptions about the pricing of an asset or liability.
	In accordance with the fair value hierarchy described above, the following table shows the fair value of the Company's financial assets and liabilities that are required to be measured on a recurring basis at fair value as of December 31, 2013 and December 31, 2012.
						Level One				Level Two				Level Three
		Balance at		Balance at		Balance at		Balance at		Balance at		Balance at		Balance at		Balance at
		December		December		December		December		December		December		December		December
		31, 2013		31, 2012		31, 2013		31, 2012		31, 2013		31, 2012		31, 2013		31, 2012
		(In thousands)
	Assets:
	Available-for-sale Securities:
	Equity securities -
	common shares	$	17,454	$	6,369	$	17,454	$	6,369		-		-		-		-
	Restricted cash and investments:
	Money market funds	$	1,371	$	1,231	$	1,371	$	1,231		-		-		-		-
	Trading Securities:
	Debt securities -
	municipal securities	$	2,232	$	2,716		-		-	$	2,232	$	2,716		-		-
	At December 31, 2013, the Company had $17.5 million of marketable equity securities that were classified as available-for-sale securities and carried at fair value, with unrealized gains and losses recorded as a component of accumulated other comprehensive income in shareholders' equity. Realized gains and losses, and declines in value judged to be other-than-temporary, on available-for-sale securities are included in the determination of net income. For the year ended December 31, 2013, realized gains from sales of available-for-sale securities of approximately $1.2 million, net of tax impact of $0.7 million, were reclassified from accumulated other comprehensive income and included in net income. Current period changes in unrealized gains from available-for-sale securities of approximately $3.7 million, net of tax impact of $2.3 million were recorded during 2013. The Company used specific identification to determine the amount reclassified out of accumulated other comprehensive income into earnings. As of December 31, 2013, these available-for-sale marketable equity securities are included in "Other long-term assets and restricted cash." Accumulated unrealized income of $4.6 million net of an estimated tax impact of $2.8 million, are included in accumulated other comprehensive income as at December 31, 2013, and accumulated unrealized losses of $302,000, net of an estimated tax impact of $185,000, was included in accumulated other comprehensive loss as at December 31, 2012.

Note_3_Line_of_Credit_and_Long

Note 3 - Line of Credit and Long-Term Debt	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Long-term Debt [Text Block]	'
	3.     Line of Credit and Long-Term Debt
	The Company maintained a revolving line of credit with Wells Fargo Bank, which permitted revolving borrowings and letters of credit. Previously, the line of credit had been maintained at $150.0 million with interest at either the prime rate, or LIBOR plus 0.625%. In October 21, 2013, the Company increased this limit to $300.0 million, and going forward it will bear interest at either the prime rate, or LIBOR plus 0.750%, determined at the time of borrowing, and has a maturity date of October 21, 2016. The Company had $38.0 million and $80.0 million outstanding under the line of credit as of December 31, 2013 and 2012, respectively. The weighted average variable annual percentage rate ("APR") for amounts borrowed in 2013 was 1.04%, and 0.94% for amounts borrowed in 2012. Borrowing under the line of credit is recorded in the "Long-term debt" line of the consolidated balance sheets. In connection with our self-insurance program, as of December 31, 2013, the Company also utilized $24.0 million of the line of credit for letters of credit issued to various regulatory authorities. Considering the increase in the line of credit limit noted above, the Company has $238.0 million available for future borrowings. The Company is obligated to comply with certain financial and other covenants under the line of credit agreement and was in compliance with such covenants at December 31, 2013.

Note_4_Income_Taxes

Note 4 - Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Income Tax Disclosure [Text Block]	'
	4.     Income Taxes
	Income tax expense consists of the following (in thousands):
		2013			2012			2011
	Current income taxes:
	Federal	$	46,445		$	42,280		$	6,466
	State		5,573			4,709			3,602
			52,018			46,989			10,068
	Deferred income taxes:
	Federal		(5,520	)		(2,403	)		30,087
	State		182			428			325
			(5,338	)		(1,975	)		30,412
		$	46,680		$	45,014		$	40,480
	The effective income tax rate is different than the amount that would be computed by applying statutory corporate income tax rates to income before income taxes. The differences are summarized as follows (in thousands):
		2013			2012			2011
	Tax at the statutory rate (35%)	$	40,846		$	38,422		$	35,416
	State income taxes, net of federal benefit		3,804			3,489			2,667
	Nondeductible driver per diem		1,807			1,989			1,984
	Other, net		223			1,114			413
		$	46,680		$	45,014		$	40,480
	The net effect of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, 2013 and 2012 are as follows (in thousands):
		2013			2012
	Short-term deferred tax assets (liabilities):
	Claims accrual	$	2,460		$	2,317
	Stock options		2,254			2,257
	Other		882			1,137
	Prepaid expenses deducted for tax purposes		(2,237	)		(2,302	)
	Short-term deferred tax assets, net	$	3,359		$	3,409
	Long-term deferred tax liabilities (assets):
	Property and equipment depreciation	$	143,488		$	150,525
	Claims accrual		(984	)		(5,654	)
	Long-term deferred liabilities, net	$	142,504		$	144,871
	For the years ended December 31, 2013, 2012, and 2011, the Company does not have any uncertain tax positions, nor any unrecognized tax benefits based upon an analysis of the Company’s historic and future tax positions. There are no tax uncertainties for which it is reasonably possible an amount of unrecognized tax benefit should be recognized. Unrecognized tax benefits are defined as the difference between a tax position taken or expected to be taken in a tax return and the benefit recognized and measured pursuant to ASC Topic 740.
	The Company files federal and state income tax returns with varying statutes of limitations. The 2010 through 2013 tax years generally remain subject to examination by the federal authority, and the 2009 through 2013 tax years generally remain subject to examination by state tax authorities. The Company does not believe the unrecognized tax benefits will change significantly over the next 12 months.

Note_5_Commitments_and_Conting

Note 5 - Commitments and Contingencies	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies Disclosure [Text Block]	'
	5.     Commitments and Contingencies
	a.     Purchase Commitments
	The Company's purchase commitments for 2014 total $68.9 million, which primarily consists of revenue equipment, net of equipment trade-ins from contracted vendors, and a carry forward of approximately $8.5 million from 2013 contracts. The Company generally has the option to cancel with advanced notice ranging from 9 weeks to 90 days prior to the scheduled production.
	b.     Investment Commitments
	The Company’s commitment to invest in Transportation Resource Partners ("TRP") is $5.5 million. The carrying value of the Company's investment in TRP was $2.0 million at December 31, 2013 and $2.2 million at December 31, 2012. The Company’s commitment to invest in Transportation Resource Partners III, LP ("TRP III") is $15.0 million. As of December 31, 2013, the Company has contributed approximately $10.8 million to TRP III, leaving an outstanding commitment of $4.2 million as of December 31, 2013.
	c.     Operating Leases
	The Company periodically leases certain service center building facilities under non-cancelable operating leases. The Company also has operating leases for trailer storage. Rent expense under operating leases was approximately $2.2 million, $2.4 million, and $2.5 million for the years ended December 31, 2013, 2012, and 2011, respectively. Rent expense for these facilities is included as an operating expense under "Miscellaneous operating expenses" on the Company's consolidated statements of income.
	Periodically the Company leases revenue equipment and communication equipment under non-cancelable operating leases. The Company did not lease any revenue equipment under non-cancelable operating leases in 2013, 2012, or 2011. Communication equipment under non-cancelable operating leases expired in 2012.
	Future minimum lease payments under non-cancelable operating leases as of December 31, 2013 are as follows:
	Year Ending	Amount
	December 31,	(In thousands)
	2014	$	1,429
	2015		1,255
	2016		1,238
	2017		1,272
	2018 & thereafter		407
	Total	$	5,601
	d.     Other
	The Company is involved in certain claims and pending litigation arising in the normal course of business.  These proceedings primarily involve claims for personal injury or property damage incurred in the transportation of freight or for personnel matters.  The Company maintains insurance to cover liabilities arising from the transportation of freight in amounts in excess of self-insurance retentions, and accrues for estimated self-insured claims liabilities as described in Note 6.  Based on present knowledge of the facts and, in certain cases, advice of outside counsel, management believes the resolution of claims and pending litigation, taking into account existing reserves, will not have a materially adverse effect on the Company's financial position or results of operations.  However, the final disposition of these matters and the impact of such final dispositions cannot be determined at this time.
	The Company is also involved in certain class action litigation in which the plaintiffs allege claims for failure to provide meal and rest breaks, unpaid wages, unauthorized deductions and other items.  Based on its knowledge of the facts and advice of outside counsel, management does not believe the outcome of the litigation is likely to have a materially adverse effect on the Company's financial position or results of operations.  However, the final disposition of these matters and the impact of such final dispositions cannot be determined at this time.

Note_6_Claims_Accrual

Note 6 - Claims Accrual	12 Months Ended
	Dec. 31, 2013
Claims Accrual [Abstract]	'
Claims Accrual [Text Block]	'
	6.     Claims Accrual
	The primary claims arising for the Company consist of auto liability (personal injury and property damage), cargo liability, collision, comprehensive and workers' compensation. The Company is insured against auto liability claims under a SIR policy with retention ranging from $1.0 million to $3.0 million per occurrence and in some years, depending on the applicable policy year, the Company has been responsible for aggregate losses up to $1.5 million. For the policy year February 1, 2013 to January 31, 2014 the Company's SIR was $3.0 million with no responsibility for additional aggregate losses. For the policy period February 1, 2014 to March 1, 2015 the Company's SIR is $2.5 million with no additional responsibility for "aggregate" losses. The Company is also self-insured for workers' compensation coverage, with a self-retention level of a maximum $500,000 per occurrence. The Company establishes reserves to cover these self-insured liabilities and maintains insurance to cover liabilities in excess of those amounts. The Company's insurance policies provide for excess personal injury and property damage liability up to a total of $105.0 million per occurrence, which also includes a separate $2.5 million dollar aggregate deductible.
	The Company also maintains excess coverage for employee medical expenses and hospitalization. The self- retention amount for employee medical health was $225,000 per claimant for 2013 and 2012, and will remain this amount for 2014.
	The Company's claims reserves are classified separately between current and long-term in the balance sheet. The current and long-term balance of the Company's claims reserves at December 31, 2013 and 2012 are as follows:
		2013			2012
		(In thousands)
	Auto reserves	$	15,432		$	15,333
	Workers' compensation reserves		6,479			8,887
	Employee medical reserves		2,594			2,012
	Total reserves	$	24,505		$	26,232
	Current portion	$	15,616		$	15,892
	Long-term portion	$	8,889		$	10,340
	A reconciliation of the beginning and ending amount of the Company's claims reserves for the years ended December 31, 2013 and 2012 is as follows:
		2013			2012
		(In thousands)
	Beginning Balance	$	26,232		$	21,568
	Provisions recorded		43,797			52,140
	Claims paid and direct expenses		(45,524	)		(47,476	)
	Total reserves	$	24,505		$	26,232
	The provision recorded for the year ended December 31, 2013 is comprised of $29.1 million for insurance and claims expense, which is included in the "Insurance and claims" line of the consolidated statements of income, $5.5 million for workers' compensation expense, and $9.2 million for medical expense, both of which are included in the "Salaries, wages and benefits" line of the consolidated statements of income. The provision recorded for the year ended December 31, 2012 is comprised of $32.1 million for insurance and claims expense, $6.1 million for workers' compensation expense, and $13.9 million for medical expense.

Note_7_Related_Party_Transacti

Note 7 - Related Party Transactions	12 Months Ended
	Dec. 31, 2013
Related Party Transactions [Abstract]	'
Related Party Transactions Disclosure [Text Block]	'
	7.     Related Party Transactions
	We have provided general business loans to US West Agriculture Exporters, LLC, ("USW") a company that transacted business with our drayage operation, and in which Larry Knight is a 33% owner. Larry Knight is an employee of the Company and the brother of Kevin Knight and Keith Knight, our Chief Executive Officer and Chief Operating Officer, respectively. The loan balance including interest due from USW at December 31, 2013, was approximately $748,000, compared to approximately $2.8 million at December 31, 2012. The principal loan and interest balance is recorded in "Related party notes and interest receivable" on our consolidated balance sheets.
	Subsequent to the year-ended December 31, 2013, the Company received full payment for the remaining balance of the loan to USW.

Note_8_Shareholders_Equity

Note 8 - Shareholders' Equity	12 Months Ended
	Dec. 31, 2013
Stockholders' Equity Note [Abstract]	'
Stockholders' Equity Note Disclosure [Text Block]	'
	8.     Shareholders' Equity
	During 2013, 2012, and 2011, certain non-employee Board of Director members received annual director fees through the issuance of common stock in equivalent shares. The table below reflects this activity for the years as presented.
		2013		2012		2011
	Annual director fees paid through stock issuance	$	167,946	$	148,437	$	112,493
	Shares of common stock issued		9,885		9,040		6,495
	Dividends paid per common share	$	0.24	$	0.74	$	0.24

Note_9_StockBased_Compensation

Note 9 - Stock-Based Compensation and Employee Benefit Plans	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]	'
	9.     Stock Based Compensation and Employee Benefit Plans
	a.     Stock-Based Compensation
	In May 2012, our shareholders approved the 2012 Equity Compensation Plan (the "2012 Plan").  The 2012 Plan replaced the Amended and Restated 2003 Stock Option and Equity Compensation Plan, as amended and restated in May 2009 (the "2003 Plan").  Grants outstanding under the 2003 Plan continue in force and effect, but any grants of stock-based compensation after May 18, 2012, were made under the 2012 Plan.
	The 2012 Plan is administered by the Compensation Committee of the Board of Directors (the "Compensation Committee").  The Compensation Committee has discretion to determine the number of shares subject to each grant and the terms and conditions of each grant, subject to the general limitations of the 2012 Plan, but in any calendar year, no single grant may exceed 650,000 shares.  The Compensation Committee may award incentive stock options, non-qualified stock options, restricted stock grants, restricted stock units or stock appreciation rights to employees and officers.  Incentive stock options are designed to comply with the applicable provisions of the Internal Revenue Code (the "Code") and are subject to restrictions within the Code.  Vesting schedules for grants are set by the Compensation Committee and vary according to the goals of the grant.  Grants, including stock options, must be granted with exercise price equal to the fair market value, determined by the closing price of the stock on the date the grant is made, as reported by the New York Stock Exchange.  The exercise price of stock options granted may not be modified.  Most stock options granted by the Company cannot be exercised until at least one (1) year after the date of grant and are forfeited upon termination of employment for reasons other than death, disability, or retirement.  The 2012 Plan reserves 4 million shares for the grant of equity compensation awards, of which 200,000 shares are reserved for issuance to outside directors.  The 2012 Plan will terminate on May 16, 2022.
	From 2003 to 2006, independent directors received automatic grants of non-qualified stock options upon joining the Board of Directors and annually thereafter. In 2007, Company's Board of Directors adopted a new compensation structure for independent directors, whereby the practice of making automatic grants to independent directors was discontinued. Under the new structure, effective February 2007, independent directors receive annual compensation that is payable 50% in cash and 50% in common stock.
	Stock-based compensation charges were approximately $2.8 million, $6.3 million, and $3.5 million for the years ended December 31, 2013, 2012, and 2011, respectively, which reduced income from operations accordingly. Stock-based compensation expense recognized is based on awards ultimately expected to vest and has been reduced for estimated forfeitures. ASC 718 requires forfeitures to be estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates.
	In 2012, the Compensation Committee of the Board of Directors approved the accelerated vesting of certain stock options issued prior to 2009, resulting in approximately $4.0 million of pre-tax stock compensation expense ($3.9 million after tax) in that year.
	The Company received $4.3 million, $3.6 million, and $2.0 million in cash from the exercise of stock options during the years ended December 31, 2013, 2012 and 2011, respectively. There was no excess tax benefit in 2013 and the excess tax benefit realized for the tax deductions from the exercise of options of the share-based payment arrangements for the years ended December 31, 2012 and 2011, was approximately $30,000, and $60,000, respectively. This tax benefit also decreased cash provided by operating activities, and increased cash provided by financing activities by the same amount for all years presented.
	The fair value of each option grant is estimated on the date of grant using the Black-Scholes option valuation model. Listed below are the weighted average assumptions used for the fair value computation:
			Year Ended December 31,
			2013			2012		2011
	Dividend yield (1)			1.54	%	N/A			1.58	%
	Expected volatility (2)			24.92	%	N/A			33.73	%
	Risk-free interest rate (3)			0.34	%	N/A			0.38	%
	Expected terms (years) (4)			2.74		N/A			3.92
	Weighted average fair value of options granted		$	2.25		N/A		$	3.48
	-1	The dividend yield is based on the Company's historical experience and future expectation of dividend payouts.
	-2	The Company analyzed the volatility of its stock using historical data for the past seven years to through the end of the most recent period to estimate expected volatility.
	-3	The risk-free interest rate assumption is based on U.S. Treasury securities at a constant maturity with a maturity period that most closely resembles the expected term of the stock option award.
	-4	The expected terms of employee stock options represents the weighted-average period the stock options are expected to remain outstanding and has been determined based on historical exercise behavior for the past seven years through the end of the most recent period.
	As of December 31, 2013, there was $1.2 million of unrecognized compensation cost related to unvested stock option compensation awards granted under the 2012 Equity Compensation Plan and our prior stock option plan. That cost is expected to be recognized over a weighted-average period of 2.1 years, and a total period of 3.9 years.
	A summary of the award activity for the years ended December 31, 2013, 2012, and 2011 is presented below:
			2013								2012					2011
			Options				Weighted				Options			Weighted		Options			Weighted
							Average							Average					Average
							Exercise							Exercise					Exercise
							Price							Price					Price
	Outstanding at beginning of year			3,424,806			$	15.99				3,823,585		$	15.8		4,144,476		$	15.68
	Granted			429,800				15.62				-		$	0		109,500		$	15.15
	Exercised			(345,302	)			12.6				(281,993	)	$	12.85		(189,788	)	$	10.53
	Forfeited and Expired			(134,458	)			16.78				(116,786	)	$	17.13		(240,603	)	$	16.72
	Outstanding at end of year			3,374,846				16.26				3,424,806		$	15.99		3,823,585		$	15.8
	Vested and exercisable at end of year			2,828,245				16.27				3,174,843		$	15.86		2,314,558		$	15.32
	Weighted average fair value of options granted during the period							2.25						N/A					$	3.48
	As of December 31, 2013, the number of options that were currently vested and expected to become vested was 3,330,735. These options have a weighted-average exercise price of $16.27, a weighted-average contractual remaining term of 3.08 years, and an aggregate intrinsic value of $7.1 million.
	The following table summarizes information about stock options to purchase the Company's common stock at December 31, 2013:
		Range of					Shares				Weighted Avg.			Weighted Avg.		Number Vested			Weighted
		Exercise					Outstanding				Contractual			Exercise Price		and Exercisable			Avg. Exercise
		Prices									Years			Per Share					Price Per
											Remaining								Share for
																			Vested and
																			Exercisable
		$8.42	-	10.52				2,610				0.34			$10.37		2,610			$10.37
		$10.53	-	12.63				181,664				0.45			$11.80		181,664			$11.40
		$12.63	-	14.73				160,690				1.42			$14.45		156,790			$14.47
		$14.74	-	16.83				1,702,830				3.08			$15.44		1,271,209			$15.40
		$16.84	-	18.94				1,294,052				3.77			$18.11		1,186,972			$18.04
		$18.95	-	21.05				33,000				2.84			$20.03		29,000			$20.14
		Overall Total						3,374,846				3.12			$16.26		2,828,245			$16.27
	The total intrinsic value of options exercised during the twelve-month period was $1.5 million, $1.3 million, and $1.2 million in 2013, 2012, and 2011, respectively. Based on the market price as of December 31, 2013, the intrinsic value of options outstanding as of December 31, 2013 was approximately $7.3 million, and the intrinsic value of options exercisable for the same period was approximately $6.0 million. The weighted average remaining contractual life as of December 31, 2013 for vested and exercisable options is 2.71 years.
	Since 2009, the Company has issued restricted stock units (RSUs) to its employees. The Company's RSU program consists of service based awards that vest gradually over a period ranging from 5 to 13 years. In 2011, the Company issued 123,500 RSUs with a market value ranging from $14.96 to $15.15 per share based on the closing market price on the date of issuance. In 2012, the Company issued 41,000 RSUs with a market value of $16.76 per share based on the closing market price on the date of issuance. In 2013, the Company issued 183,111 RSUs with a market value of $15.95 per share based on the closing market price on the date of issuance. Stock compensation expense for these RSUs is being amortized using the straight-line method over the vesting period. As of December 31, 2013, the Company had approximately $15.8 million of unrecognized compensation expense related to restricted stock awards, which will be recognized over a weighted average period of 4.4 years.
	RSUs not yet vested are entitled to accumulate quarterly cash dividends that are paid to shareholders holding outstanding shares of the Company's common stock. Accrued dividends are paid to recipients as the RSUs vest. Accrued dividends are forfeited if RSUs are canceled or terminated. Dividends paid under the RSU program are charged to retained earnings.
	The following tables summarize the Company's restricted stock award activity for the fiscal years ended December 31, 2013, 2012, and 2011:
			2013								2012					2011
			Number of				Weighted				Number of			Weighted		Number of			Weighted
			Restricted				Average				Restricted			Average		Restricted			Average
			Stock Awards				Grant Date				Stock Awards			Grant Date		Stock Awards			Grant Date
							Fair Value							Fair Value					Fair Value
	Unvested at January 1
	Unvested at January 1,			1,210,532			$	16.04				1,325,817		$	16.01		1,364,560		$	16.11
	Granted			183,111			$	15.95				41,000		$	16.76		123,500		$	15.03
	Vested			(130,265	)		$	16.01				(114,605	)	$	16		(81,513	)	$	16.11
	Forfeited and Expired			(49,680	)		$	15.75				(41,680	)	$	15.97		(80,730	)	$	16.07
Outstanding (unvested) at end of year			1,213,698			$	16.04				1,210,532		$	16.04		1,325,817		$	16.01
b.     401(k) Profit Sharing Plan
The Company has a 401(k) profit sharing plan (the "Plan") for all employees who are 19 years of age or older and have completed one year of service with the Company. The Plan provides for a mandatory matching contribution equal to 50% of the amount of the employee's salary deduction not to exceed $850 annually per employee. The Plan also provides for a discretionary matching contribution. In 2013, 2012, and 2011, there were no discretionary contributions. Employees' rights to employer contributions vest after five years from their date of employment. The Company's mandatory matching contribution was approximately $326,000, $266,000, and $273,000 in 2013, 2012, and 2011, respectively.

Note_10_Company_Share_Repurcha

Note 10 - Company Share Repurchase Program	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block Supplement [Abstract]	'
Treasury Stock [Text Block]	'
	10.     Company Share Repurchase Program
	On November 13, 2008, the Company's Board of Directors unanimously authorized the repurchase of up to 3.0 million shares of the Company's common stock. As of December 31, 2010, there were 2,020,956 shares remaining under the 2008 authorization. On May 19, 2011, the Company's Board of Directors unanimously authorized the repurchase of an additional 10.0 million shares of the Company's common stock. The repurchase authorization is intended to afford the Company flexibility to acquire shares opportunistically in future periods and does not indicate an intention to repurchase any particular number of shares within a definite timeframe. Any repurchases would be effected based upon share price and market conditions.
	Under the share repurchase program, the Company repurchased 4,582,400 shares of the Company's common stock in the open market for approximately $76.6 million for the year ended December 31, 2011, and no shares were repurchased in the years ended December 31, 2012 or 2013. The shares acquired have been retired and are available for future issuance. The purchases were made in accordance with Securities and Exchange Commission Rule 10b-18, which limits the amount and timing of repurchases. As of December 31, 2013, there were 7,438,556 shares remaining for future purchases under the repurchase program. The repurchase authorization will remain in effect until the share limit is reached or the program is terminated.

Note_11_Segment_Information

Note 11 - Segment Information	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Segment Reporting Disclosure [Text Block]	'
	11.     Segment Information
	The Company has two operating segments: (i) the Asset-Based segment comprised of three operating units (DryVan, Refrigerated, and Drayage), and (ii) the Non-Asset-Based segment comprised of two operating units (Brokerage and Intermodal). The Company also provides logistics, freight management and other non-trucking services through its Non-Asset-Based businesses. Through its Asset-Based and Non-Asset-Based segment capabilities, the Company is able to transport, or can arrange for the transportation of, general commodities for customers throughout the United States and parts of Canada and Mexico.
	Prior to fourth quarter 2013, the Company aggregated the Asset-Based and Non-Asset-Based segments in accordance with relevant accounting guidance regarding segment reporting. Based on the Company's 2013 evaluation, the Company concluded that because of evolving events and changes to its business, that separate segment reporting of the Company's Asset-Based business and Non-Asset-Based business is appropriate.
	The Company, in determining its reportable operating segments, focuses on financial information such as operating revenues and expenses, operating income, operating ratios, and other key operating statistics common in the industry. The chief operating decision makers also use this information to evaluate segment performance and allocate resources to the Company’s operations.
	The Company’s operating segments provide transportation and related services for one another. Such services are billed at cost, and no profit is earned. Such intersegment revenues and expenses are eliminated in the Company’s consolidated results.
	Asset-Based Segment Information
	The Asset-Based trucking units operate large modern company-owned tractor fleets and use independent contractors to provide various transportation solutions, including multiple stop pick-ups and deliveries, dedicated equipment and personnel, on-time expedited pick-ups and deliveries, specialized driver training, and other truckload services. Revenues are generally set at a predetermined rate per mile or per load for the Asset-Based trucking services. In addition, revenue streams are also generated by charging for tractor and trailer detention, loading and unloading activities, dedicated services, and other specialized services, as well as through the collection of fuel surcharges to mitigate the impact of increases in the cost of fuel.
	The primary measurement the Company uses to evaluate the profitability of the Asset-Based segment is operating ratio, measured both on a GAAP basis (operating expenses expressed as a percentage of revenue) and non-GAAP basis used by many in the Company’s industry (operating expenses, net of Asset-Based fuel surcharge revenue, expressed as a percentage of Asset-Based revenue, excluding Asset-Based fuel surcharge revenue). The Company believes the second method allows them to more effectively compare periods while excluding the potentially volatile effect of changes in fuel prices. The tables below compare operating ratio using both methods.
	The following table sets forth the Asset-Based segment operating ratio on a GAAP basis.
			2013					2012					2011
	Asset-Based (amounts in thousands)		$			%		$			%		$			%
	Revenue		$	822,188				$	836,357				$	785,989
	Operating expenses			716,021			87.1		733,344			87.7		691,006			87.9
	Operating income		$	106,167				$	103,013				$	94,983
	The following table sets forth the Asset-Based segment operating ratio as if fuel surcharges are excluded from total revenue and instead reported as a reduction of operation expenses, excluding intersegment activity.
			2013					2012					2011
	Asset-Based (amounts in thousands)		$			%		$			%		$			%
	Revenue		$	822,188				$	836,357				$	785,989
	Less: Asset-Based fuel surcharge revenue			(177,386	)				(183,885	)				(168,913	)
	Less: Intersegment transactions(1)			(120	)				(112	)				(82	)
	Revenue, net of fuel surcharge and intersegment transactions(1)			644,682					652,360					616,994
	Operating expenses			716,021					733,344					691,006
	Less: Asset-Based fuel surcharge revenue			(177,386	)				(183,885	)				(168,913	)
	Less: Intersegment transactions(1)			(120	)				(112	)				(82	)
	Operating expenses, net of fuel surcharge and intersegment transactions(1)			538,515			83.5		549,347			84.2		522,011			84.6
	Operating income		$	106,167				$	103,013				$	94,983
	-1	These items represent non-GAAP financial measures and are not substitutes for, and should be considered in addition to, the GAAP financial measures presented in the previous table.
	The Company’s Asset-Based segment requires substantial capital expenditures for purchases of new revenue equipment.  Total depreciation and amortization expense for the Asset-Based Segment was approximately $81.0 million, $79.7 million, and 72.5 million in 2013, 2012, and 2011, respectively.
	Non-Asset-Based Segment Information
	Non-Asset-Based revenue is generated primarily by the Brokerage and Intermodal operating units, which charges a predetermined rate per mile or per load for arranging freight transportation for its customers. The Company also provides logistics, freight management and other non-trucking services through its Non-Asset-Based business. Additional revenue is generated by offering specialized logistics solutions (including, but not limited to, origin management, surge volumes, disaster relief, special projects, and other logistics needs). Non-Asset-Based revenue is mainly affected by the rates the Company is able to negotiate with clients, the freight volumes that are shipped through third-party capacity providers and the Company’s ability to secure qualified third-party capacity providers to transport customer freight. This segment has seen continued growth in the number of shipments serviced by the Brokerage and Intermodal operating units, and contributed to the improved productivity and revenue realized in 2013.
	The following table sets forth the Non-Asset-Based segment revenue, other operating expenses, and operating income.
			2013					2012					2011
	Non-Asset-Based (amounts in thousands)		$			%		$			%		$			%
	Revenue		$	151,194				$	105,794				$	86,449
	Other operating expenses			143,452			94.9		100,540			95		81,411			94.2
	Operating income		$	7,742				$	5,254				$	5,038
	The following table sets forth the Non-Asset-Based revenue, operating expenses, and operating income, excluding intersegment transactions.
			2013					2012					2011
	Non-Asset-Based (amounts in thousands)		$			%		$			%		$			%
	Revenue		$	151,194				$	105,794				$	86,449
	Less: Intersegment transactions			(4,025	)				(6,003	)				(6,157	)
	Revenue excluding intersegment transactions			147,169					99,791					80,292
	Operating expenses			143,452					100,540					81,411
	Less: Intersegment transactions			(4,025	)				(6,003	)				(6,157	)
	Operating expenses excluding intersegment transactions			139,427			94.7		94,537			94.7		75,254			93.7
	Operating income		$	7,742				$	5,254				$	5,038
	The Company primarily measures the Non-Asset-Based segment's profitability by reviewing the gross margin percentage (revenue, less purchased transportation expense, expressed as a percentage of revenue) and the operating income percentage. The gross margin percentage can be affected by customer rates and the costs of securing third-party capacity providers. The Company’s third-party capacity providers are generally not subject to long-term or predetermined contracted rates, and the operating results could be affected if the availability of third-party capacity providers or the rates for such providers change in the future. The following table lists the gross margin percentage for the Company’s Brokerage and Intermodal businesses.
			2013			2012		2011
	Brokerage gross margin percent (1)			13.30%			13.60%		11.70%
	Intermodal gross margin percent(1)			10.70%			12.00%		8.20%
	-1			Gross margin percentage is based on revenue net of intersegment elimination.
	The Company’s Non-Asset-Based segment does not require significant capital expenditures and is not asset-intensive like the Asset-Based segment. Total Non-Asset-Based segment depreciation and amortization expense is primarily attributed to equipment leased to third parties, which totaled to approximately $5.1 million, $5.3 million, and $3.3 million in 2013, 2012, and 2011, respectively.
	No segmental asset information is provided as the company does not prepare balance sheets by segment, and the chief operating decision makers do not review segment assets to make operating decisions.

Note_12_Quarterly_Financial_Da

Note 12 - Quarterly Financial Data (unaudited)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Quarterly Financial Information [Text Block]	'
	12.     Quarterly Financial Data (unaudited)
	The following table sets forth certain unaudited information about the Company's revenue and results of operations on a quarterly basis for 2013 and 2012 (amount in thousands, except per share data):
		2013
		31-Mar		30-Jun		30-Sep		31-Dec
	Revenue, before fuel surcharge		189,600		200,104		195,847		206,300
	Income from operations		25,544		31,925		24,274		32,165
	Net income attributable to Knight		15,183		18,939		15,059		20,101
	Earnings per common share:
	Basic	$	0.19	$	0.24	$	0.19	$	0.25
	Diluted	$	0.19	$	0.24	$	0.19	$	0.25
		2012
		31-Mar		30-Jun		30-Sep		31-Dec
	Revenue, before fuel surcharge	$	175,599	$	188,838	$	192,550	$	195,164
	Income from operations	$	19,834	$	32,103	$	27,767	$	28,564
	Net income attributable to Knight	$	10,546	$	19,289	$	16,584	$	17,698
	Earnings per common share:
	Basic	$	0.13	$	0.24	$	0.21	$	0.22
	Diluted	$	0.13	$	0.24	$	0.21	$	0.22

Note_13_Subsequent_Events

Note 13 - Subsequent Events	12 Months Ended
	Dec. 31, 2013
Subsequent Events [Abstract]	'
Subsequent Events [Text Block]	'
	13.     Subsequent Events
	In preparing these financial statements, the Company has evaluated events after December 31, 2013. As described in Note 7, "Related Party Transactions," of these financial statements, subsequent to the year-end, the Company has received payment of $748,452 from one of the members of US West Agriculture Exporters, LLC, representing full payment for the outstanding loan balance as of December 31, 2013.

Schedule_II_Valuation_and_Qual

Schedule II - Valuation and Qualifying Accounts and Reserves	12 Months Ended
	Dec. 31, 2013
Valuation and Qualifying Accounts [Abstract]	'
Schedule of Valuation and Qualifying Accounts Disclosure [Text Block]	'
	SCHEDULE II
	KNIGHT TRANSPORTATION, INC. AND SUBSIDIARIES
	Valuation and Qualifying Accounts and Reserves
	For the Years Ended December 31, 2013, 2012 and 2011
	(In thousands)
		Balance at		Provision for			Bad Debt			Balance at
		Beginning		Bad Debt			Write-offs			End of Period
		of Period
	Allowance for doubtful trade receivables:
	Year ended December 31, 2013	$	1,917	$	952		$	(460	)	$	2,409
	Year ended December 31, 2012	$	1,651	$	931		$	(665	)	$	1,917
	Year ended December 31, 2011	$	2,355	$	326		$	(1,030	)	$	1,651
		Balance at		Provision for			Bad Debt			Balance at
		Beginning		Credit Losses			Write-offs			End of Period
		of Period
	Allowance for doubtful notes receivable:
	Year ended December 31, 2013	$	291	$	55		$	(34	)	$	312
	Year ended December 31, 2012	$	416	$	(48	)	$	(77	)	$	291
	Year ended December 31, 2011	$	480	$	252		$	(316	)	$	416

Accounting_Policies_by_Policy_

Accounting Policies, by Policy (Policies)	12 Months Ended
	Dec. 31, 2013
Accounting Policies, by Policy (Policies) [Line Items]	'
Consolidation, Policy [Policy Text Block]	'
	Principles of Consolidation - The accompanying consolidated financial statements include Knight Transportation, Inc. and its wholly owned and controlled subsidiaries. The Company's non-controlling interests in subsidiaries are not significant. All intercompany accounts and transactions are eliminated upon consolidation.
Use of Estimates, Policy [Policy Text Block]	'
	Use of Estimates - The preparation of financial statements in conformity with United States 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 consolidated financial statements. Estimates and assumptions equally apply to the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Cash and Cash Equivalents, Policy [Policy Text Block]	'
	Cash and Cash Equivalents - Cash and cash equivalents are comprised of cash, money market funds, and short-term, highly liquid instruments with insignificant interest rate risk and original maturities of three months or less. Cash balances with institutions may be in excess of Federal Deposit Insurance Corporation ("FDIC") limits or may be invested in sweep accounts that are not insured by the institution, the FDIC or any other government agency.
Finance, Loans and Leases Receivable, Policy [Policy Text Block]	'
	Notes Receivable – The Company provides financing to independent contractors and third parties on equipment sold or leased under the Company's equipment sale program. Most of the notes are collateralized and are due in weekly installments, including principal and interest payments, ranging from 2.0% to 20%. The Company had 117 and 126 loans outstanding from independent contractors and third parties as of December 31, 2013 and 2012, respectively.
	The notes receivable balances are classified separately between current and long-term notes in the consolidated balance sheets. The current and long-term balances of our notes receivables as of December 31, 2013 and 2012 are as follows:
		2013			2012
		(In thousands)
	Notes receivable from independent contractors	$	503		$	605
	Notes receivable from third parties		4,630			4,169
	Gross notes receivable		5,133			4,774
	Allowance for doubtful notes receivable		(312	)		(291	)
	Total notes receivable, net of allowance	$	4,821		$	4,483
	Current portion, net of allowance		774			791
	Long-term portion	$	4,047		$	3,692
Disclosure of Long Lived Assets Held-for-sale [Table Text Block]	'
	Assets Held for Sale - The Company had $16.5 million and $18.4 million of revenue equipment not being utilized in operations, which is classified as assets held for sale, as of December 31, 2013 and 2012, respectively. Assets held for sale are recorded at the lower of depreciated value or fair market value less selling costs and are not subject to depreciation. The Company periodically reviews the carrying value of these assets for possible impairment. No impairment was recorded in 2013 or 2012. The Company expects to sell these assets within 12 months.
Inventory, Policy [Policy Text Block]	'
	Other Current Assets - Included in other current assets are inventories of tires, spare parts, and fuel.
Property, Plant and Equipment, Policy [Policy Text Block]	'
	Property and Equipment - Property and equipment is stated at cost less accumulated depreciation. Property and equipment is depreciated to estimated salvage values using the straight-line method of depreciation over the following estimated useful lives:
		Years
	Land improvements	5	-	10
	Buildings and improvements	15	-	30
	Furniture and fixtures	3	-	10
	Shop and service equipment	2	-	5
	Revenue equipment	5	-	10
	Leasehold improvements	1	-	5
	The Company expenses repairs and maintenance as incurred. For the years ended December 31, 2013, 2012, and 2011, repairs and maintenance expense totaled approximately $30.5 million, $30.4 million, and $24.2 million, respectively. The expense is included in operations and maintenance expense in the accompanying consolidated statements of income.
	The Company periodically reviews the reasonableness of its estimates regarding useful lives and salvage values for revenue equipment and other long-lived assets based upon, among other things, the Company's experience with similar assets, conditions in the used revenue equipment market, and prevailing industry practice.
	Tires on revenue equipment purchased are capitalized as a part of the equipment cost and depreciated over the life of the vehicle. Replacement tires and recapping costs are expensed when placed in service.
Investment, Policy [Policy Text Block]	'
	Other Long-term Assets and Restricted Cash and Investments include:
		2013			2012
		(In thousands)
	Investment in Transportation Resource Partners (TRP)	$	2,035		$	2,246
	Investment in Transportation Resource Partners III (TRP III)		11,440			7,568
	Restricted Cash and Investments		3,603			3,947
	Available-For-Sale Equity Securities		17,454			6,369
	Other		1,662			1,253
		$	36,194		$	21,383
	In 2003, the Company signed a partnership agreement with TRP, a company that makes privately negotiated equity investments. According to the original partnership agreement, the Company committed to invest $5.0 million out of approximately $260.0 million total, for a 1.9% ownership interest. In early 2006, the Company increased the commitment amount to $5.5 million. Contributions to TRP are accounted for using the cost method as the level of influence over the operations of TRP is minor. The Company contributed $142,000 to TRP as an additional investment in 2011, and no additional contributions were made in 2012 or 2013. The Company received additional earn-outs of $467,000, $216,000, and $115,000 in 2013, 2012, and 2011, respectively, for disposed portfolios. The earn-outs are recognized as gains in the year received. The Company also recorded a $209,000 impairment in 2013 for an other-than-temporary loss in its investment, resulting from unrealized losses on the investments remaining within the TRP portfolio. The Company's ownership interest in TRP is approximately 1.9%, with a carrying value of $2.0 million and $2.2 million at December 31, 2013 and 2012, respectively.
	In the fourth quarter of 2008, the Company committed to invest $15.0 million in a new partnership managed and operated by the managers and principals of TRP. The new partnership, TRP III, focuses on the same investment opportunities as TRP. Since its inception, the Company has contributed approximately $10.8 million to TRP III, leaving an outstanding commitment of $4.2 million as of December 31, 2013. The investment in TRP III is accounted for using the equity method. The Company has recorded income of approximately $669,000, $261,000, and $74,000 for its investment in TRP III for years ended December 31, 2013, 2012, and 2011, respectively. At December 31, 2013, the investment balance in TRP III was $11.4 million, compared to $7.6 million at December 31, 2012. The Company's ownership interest was approximately 6.1% as at December 31, 2013.
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]	'
	Restricted Cash and Investments – In connection with the Company's self-insurance program, $3.6 million and $3.9 million have been set aside in escrow accounts to meet statutory requirements as of December 31, 2013 and 2012, respectively.
	In accordance with the provisions of ASC 210, Balance Sheet, and ASC 320, Investments – Debt and Equity Securities, the Company's investments in debt or equity securities are classified as either trading securities, held-to-maturity securities, or available-for-sale securities, based on the Company's intent with respect to those securities. Investments in debt and equity securities are classified as trading securities if they are held principally for the purpose of selling in the near term. Investments in debt securities are classified as held-to-maturity if the Company has the positive intent to hold such securities to maturity and the ability to do so. Investments in debt and equity securities not classified as trading or held-to-maturity are classified as available-for-sale.
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]	'
	Impairment of Long-Lived Assets – ASC 360-10, Property, Plant and Equipment, provides a single accounting model for the assessment of impairment of long-lived assets. In accordance with ASC 360-10, Long-lived Assets, such as property and equipment and purchased intangibles to be held and used in operations, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Long-lived assets are grouped at the lowest level at which identifiable cash flows are largely independent when assessing impairment. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated future cash flows, an impairment charge is recognized by the amount by which the carrying amount of the asset exceeds the fair value of the asset. Assets classified as held for sale are not depreciated and are presented in the Company's consolidated balance sheets at the lower of the carrying amount or fair value less costs to sell. Revenue equipment classified as held for sale is presented in "assets held for sale" on the Company's consolidated balance sheets. Recoverability of long-lived assets is dependent upon, among other things, the Company's ability to continue to achieve profitability in order to meet its obligations when they become due. In the opinion of management, based upon current information, the carrying amount of long-lived assets will be recovered by future cash flows generated through the use of such assets over their respective estimated useful lives.
Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]	'
	Goodwill & Intangibles, net - Goodwill is not amortized, but it is reviewed for impairment at least annually (December 31), or more frequently should any of the circumstances listed in ASC 350-20, Goodwill, occur. The standard permits an entity to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not the fair value of a reporting unit is less than its carrying amount. If, after assessing the totality of events or circumstances, it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, then performing the two-step impairment test is unnecessary. However, if an entity concludes otherwise, then it is required to perform the impairment test as prescribed in ASC 350-20. Goodwill is required to be tested for impairment at the reporting unit level utilizing a two-step methodology. The initial step requires the Company to determine the fair value of the reporting unit and compare it to the carrying value of such unit, including goodwill. No impairment is recognized if the fair value exceeds the carrying value; however, if the carrying value of the reporting unit exceeds its fair value, the goodwill of the reporting unit may be impaired. The amount, if any, of the impairment would then be measured in the second step. The Company completed this annual test as of December 31, 2013, and no adjustment for impairment was determined to be necessary. The Company has no accumulated goodwill impairment loss from prior years.
	During fiscal year 2006, the Company recorded approximately $1.8 million of goodwill and $310,000 of finite lived intangible assets in connection with the acquisition of most of the trucking assets of Roads West. In 2007, the Company paid Roads West $135,000 for an earn-out, representing the final earn-out under the purchase agreement. The earn-out paid in 2007 was recorded as additional goodwill related to this acquisition. The basis of goodwill for tax purposes was determined to be in excess of the book basis of goodwill. Under this circumstance, ASC 740, Income Taxes, requires that the goodwill be separated into two components for the acquisitions before the adoption of ASC 805, Business Combination. The first component is equivalent to book goodwill, and future tax amortization of this component is treated as a temporary difference, for which a deferred tax liability is established. The second component is the excess tax goodwill over the book goodwill, for which no deferred taxes are recognized. The tax benefit from the recognition of the amortization of the second component on the tax return is treated as a reduction in the book basis of goodwill. The finite lived intangible portion was amortized using the straight-line method over a five-year period, and was fully amortized as of December 31, 2011.
	The changes in the carrying amounts of goodwill were as follows:
		2013			2012
		(In thousands)
	Goodwill at beginning of period	$	10,276		$	10,295
	Amortization relating to deferred tax assets		(19	)		(19	)
	Goodwill at end of period	$	10,257		$	10,276
Claims Accrual Policy Text Block	'
	Claims Accrual - The claims reserves represent accruals for estimated pending claims within the self-insured retention ("SIR"), including adverse development of known claims and incurred but not reported claims. These estimates are based on the Company's claims experience, including claims settlement patterns, historical payment trends, the experience/knowledge of the Company's self-administered claims as well as that of the third-party administrator as it relates to workers' compensation claims, along with assumptions about future events. The most significant assumptions used in the estimation process include determining the trend in costs, the expected cost of claims incurred but not reported, and the expected costs to settle or pay outstanding claims. Changes in assumptions and changes in actual experience could cause these estimates to change significantly in the near term. A higher SIR may cause assumptions and estimates to vary more unpredictably than a lower SIR.
Revenue Recognition, Policy [Policy Text Block]	'
	Revenue Recognition - The Company recognizes revenue when persuasive evidence of an arrangement exists, delivery has occurred, the fee is fixed or determinable, and collectability is probable. These conditions are met upon delivery.
	In accordance with ASC 605-45, Revenue Recognition – Principal Agent Consideration, the Company accounts for revenue from our Asset-Based operations, our Non-Asset-Based operations, and revenue on freight transported by independent contractors on a gross basis. The Company is the primary obligor in the arrangements, the Company has the ability to establish prices, the Company has discretion in selecting the independent contractor or other third-party that will perform the service, the Company has the risk of loss in the event of cargo claims, and the Company bears credit risk with customer payments.  Accordingly, all such revenue billed to customers is classified as operating revenue and all corresponding payments to carriers for transportation services the Company arranges in connection with Brokerage and Intermodal activities and to independent contractor providers of revenue equipment are classified as purchased transportation expense.
Income Tax, Policy [Policy Text Block]	'
	Income Taxes - The Company accounts for income taxes under the asset and liability method. This method requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized as income in the period that includes the enactment date.
	The Company records a valuation allowance for deferred tax assets to the extent it believes these assets are not more likely than not to be realized. In making such determinations, the Company considers all available positive and negative evidence, including scheduled reversals of deferred tax liabilities, projected future taxable income, tax planning strategies, and recent financial operations. A valuation allowance for deferred tax assets has not been deemed necessary due to the Company's profitable operations.
	The Company recognizes a tax benefit from an uncertain tax position when it is more likely than not that the position will be sustained upon examination, including resolutions of any related appeals or litigation processes, based on the technical merits.
Fair Value of Financial Instruments, Policy [Policy Text Block]	'
	Financial Instruments- The Company's financial instruments include cash equivalents, investments held for trading, available-for-sale securities, trade receivables, notes receivable, accounts payable, and long-term debt.  Due to the short-term nature of cash equivalents, trade receivables, and accounts payable, the fair value of these instruments approximates their recorded value.  Available-for-sale and trading securities consist of marketable equity and debt securities stated at fair value. Due to the variable interest rate, the fair value of long-term debt approximates fair value.
Concentration Risk, Credit Risk, Policy [Policy Text Block]	'
	Concentration of Credit Risk - Financial instruments that potentially subject the Company to credit risk consist principally of trade receivables and notes receivable. Revenue for the Company's three largest customers accounted for approximately 11%, 10% and 12% of the total revenue for the years ended 2013, 2012 and 2011, respectively. As of December 31, 2013, balances due from the three largest customers account for approximately 6.5% of the total trade receivable balance, compared to 7.7% as of December 31, 2012. Revenue from the Company's single largest customer represented approximately 4% of total revenue for the years ended December 31, 2013 and 2012, and approximately 5% for the year ended 2011. The balance due from the single largest customer accounts for approximately 1.2% of the total trade receivable balance as of December 31, 2013, compared to 1.3% as of December 31, 2012.
Earnings Per Share, Policy [Policy Text Block]	'
	Earnings Per Share - A reconciliation of the numerator (net income) and denominator (weighted average number of shares outstanding) of the basic and diluted earnings per share ("EPS") computations for 2013, 2012, and 2011 are as follows (in thousands, except per share data):
		2013								2012						2011
		Net Income			Shares			Per Share		Net Income		Shares		Per Share		Net Income		Shares		Per Share
		(numerator)			(denominator)			Amount		(numerator)		(denominator)		Amount		(numerator)		(denominator)		Amount
	Basic EPS	$	69,282			79,994		$	0.87	$	64,117		79,673	$	0.8	$	60,248		81,439	$	0.74
	Effect of stock options & restricted stock		-			336					-		327				-		433
	Diluted EPS	$	69,282			80,330		$	0.86	$	64,117		80,000	$	0.8	$	60,248		81,872	$	0.74
	Certain shares of common stock were excluded in the computation of diluted earnings per share because the options' exercise prices were greater than the average market price of the common shares, and therefore, the effect would be anti-dilutive. A summary of those options for the twelve months ended December 31, 2013, 2012, and 2011, respectively, is as follows:
		2013			2012			2011
	Number of anti-dilutive shares		1,917,020			1,926,298			2,655,814
New Accounting Pronouncements, Policy [Policy Text Block]	'
	New Accounting Pronouncements
	In December 2013, the FASB issued ASU No. 2013-12, Definition of a Public Entity. This ASU intends to improve U.S. GAAP by providing a single definition of public business entity for use in future financial accounting and reporting guidance. The amended definition specifies that an entity that is required by the SEC to file or furnish financial statements with the SEC, or does file or furnish financial statements with the SEC, is considered a public business entity. The definition also addressed consolidated subsidiaries of public companies, stating that such an entity is not considered a public business entity for purposes of its stand-alone financial statements other than those included in an SEC filing by its parent or by other registrants or those that are issuers and are required to file or furnish financial statements with the SEC. There is no actual effective date for the amendment, however the term public business entity will be used in certain ASU's going forward.
	In February 2013, the FASB issued ASU No. 2013-02, Other Comprehensive Income. This ASU intends to improve the reporting of reclassifications out of accumulated other comprehensive income by requiring an entity to report the effect of significant reclassifications out of accumulated other comprehensive income on the respective line items in net income if the amount being reclassified is required under GAAP to be reclassified in its entirety to net income. For other amounts that are not required under GAAP to be reclassified in their entirety to net income in the same reporting period, an entity is required to cross-reference other disclosures required under GAAP that provide additional detail about those amounts. The new guidance is effective for fiscal years beginning after December 15, 2012.  The amendments do not change the current requirements for reporting net income or other comprehensive income in financial statements and the adoption of this guidance did not have a material impact on the Company's consolidated financial statements.
Allowance for Doubtful Accounts [Member]	'
Accounting Policies, by Policy (Policies) [Line Items]	'
Receivables, Trade and Other Accounts Receivable, Allowance for Doubtful Accounts, Policy [Policy Text Block]	'
	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 establishes an allowance for doubtful accounts based on historical experience and any known trends or uncertainties related to customer billing and account collectability. The Company reviews the adequacy of its allowance for doubtful accounts on a quarterly basis. Uncollectible accounts are written off when deemed uncollectible, and accounts receivable are presented net of an allowance for doubtful accounts. Historically, the Company has not had significant losses related to uncollectible accounts.
Allowance for Notes Receivable [Member]	'
Accounting Policies, by Policy (Policies) [Line Items]	'
Receivables, Trade and Other Accounts Receivable, Allowance for Doubtful Accounts, Policy [Policy Text Block]	'
	Allowance for Doubtful Notes Receivable - The Company evaluates the collectability of notes and finance lease receivables on a customer-by-customer basis. The Company establishes an allowance for credit losses based on specific customer circumstances, payment patterns, credit risk changes, and historical loss experience. The Company reviews the adequacy of its allowance for doubtful notes receivable quarterly.  Uncollectible accounts are written off when deemed uncollectible, and notes receivable are presented net of an allowance for doubtful accounts. Historically, the Company has not had significant losses related to uncollectible accounts.

Note_1_Organization_and_Summar1

Note 1 - Organization and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]	'
		2013			2012
		(In thousands)
	Notes receivable from independent contractors	$	503		$	605
	Notes receivable from third parties		4,630			4,169
	Gross notes receivable		5,133			4,774
	Allowance for doubtful notes receivable		(312	)		(291	)
	Total notes receivable, net of allowance	$	4,821		$	4,483
	Current portion, net of allowance		774			791
	Long-term portion	$	4,047		$	3,692
Scheudle of Estimated Useful Lives [Table Text Block]	'
		Years
	Land improvements	5	-	10
	Buildings and improvements	15	-	30
	Furniture and fixtures	3	-	10
	Shop and service equipment	2	-	5
	Revenue equipment	5	-	10
	Leasehold improvements	1	-	5
Schedule of Other Assets [Table Text Block]	'
		2013			2012
		(In thousands)
	Investment in Transportation Resource Partners (TRP)	$	2,035		$	2,246
	Investment in Transportation Resource Partners III (TRP III)		11,440			7,568
	Restricted Cash and Investments		3,603			3,947
	Available-For-Sale Equity Securities		17,454			6,369
	Other		1,662			1,253
		$	36,194		$	21,383
Schedule of Goodwill [Table Text Block]	'
		2013			2012
		(In thousands)
	Goodwill at beginning of period	$	10,276		$	10,295
	Amortization relating to deferred tax assets		(19	)		(19	)
	Goodwill at end of period	$	10,257		$	10,276
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	'
		2013								2012						2011
		Net Income			Shares			Per Share		Net Income		Shares		Per Share		Net Income		Shares		Per Share
		(numerator)			(denominator)			Amount		(numerator)		(denominator)		Amount		(numerator)		(denominator)		Amount
	Basic EPS	$	69,282			79,994		$	0.87	$	64,117		79,673	$	0.8	$	60,248		81,439	$	0.74
	Effect of stock options & restricted stock		-			336					-		327				-		433
	Diluted EPS	$	69,282			80,330		$	0.86	$	64,117		80,000	$	0.8	$	60,248		81,872	$	0.74
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	'
		2013			2012			2011
	Number of anti-dilutive shares		1,917,020			1,926,298			2,655,814

Note_2_Fair_Value_Measurements1

Note 2 - Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Fair Value, Assets Measured on Recurring Basis [Table Text Block]	'
						Level One				Level Two				Level Three
		Balance at		Balance at		Balance at		Balance at		Balance at		Balance at		Balance at		Balance at
		December		December		December		December		December		December		December		December
		31, 2013		31, 2012		31, 2013		31, 2012		31, 2013		31, 2012		31, 2013		31, 2012
		(In thousands)
	Assets:
	Available-for-sale Securities:
	Equity securities -
	common shares	$	17,454	$	6,369	$	17,454	$	6,369		-		-		-		-
	Restricted cash and investments:
	Money market funds	$	1,371	$	1,231	$	1,371	$	1,231		-		-		-		-
	Trading Securities:
	Debt securities -
	municipal securities	$	2,232	$	2,716		-		-	$	2,232	$	2,716		-		-

Note_4_Income_Taxes_Tables

Note 4 - Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	'
		2013			2012			2011
	Current income taxes:
	Federal	$	46,445		$	42,280		$	6,466
	State		5,573			4,709			3,602
			52,018			46,989			10,068
	Deferred income taxes:
	Federal		(5,520	)		(2,403	)		30,087
	State		182			428			325
			(5,338	)		(1,975	)		30,412
		$	46,680		$	45,014		$	40,480
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	'
		2013			2012			2011
	Tax at the statutory rate (35%)	$	40,846		$	38,422		$	35,416
	State income taxes, net of federal benefit		3,804			3,489			2,667
	Nondeductible driver per diem		1,807			1,989			1,984
	Other, net		223			1,114			413
		$	46,680		$	45,014		$	40,480
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	'
		2013			2012
	Short-term deferred tax assets (liabilities):
	Claims accrual	$	2,460		$	2,317
	Stock options		2,254			2,257
	Other		882			1,137
	Prepaid expenses deducted for tax purposes		(2,237	)		(2,302	)
	Short-term deferred tax assets, net	$	3,359		$	3,409
	Long-term deferred tax liabilities (assets):
	Property and equipment depreciation	$	143,488		$	150,525
	Claims accrual		(984	)		(5,654	)
	Long-term deferred liabilities, net	$	142,504		$	144,871

Note_5_Commitments_and_Conting1

Note 5 - Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	'
	Year Ending	Amount
	December 31,	(In thousands)
	2014	$	1,429
	2015		1,255
	2016		1,238
	2017		1,272
	2018 & thereafter		407
	Total	$	5,601

Note_6_Claims_Accrual_Tables

Note 6 - Claims Accrual (Tables)	12 Months Ended
	Dec. 31, 2013
Claims Accrual [Abstract]	'
Schedule of Accrued Liabilities [Table Text Block]	'
		2013			2012
		(In thousands)
	Auto reserves	$	15,432		$	15,333
	Workers' compensation reserves		6,479			8,887
	Employee medical reserves		2,594			2,012
	Total reserves	$	24,505		$	26,232
	Current portion	$	15,616		$	15,892
	Long-term portion	$	8,889		$	10,340
Schedule of Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block]	'
		2013			2012
		(In thousands)
	Beginning Balance	$	26,232		$	21,568
	Provisions recorded		43,797			52,140
	Claims paid and direct expenses		(45,524	)		(47,476	)
	Total reserves	$	24,505		$	26,232

Note_8_Shareholders_Equity_Tab

Note 8 - Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2013
Stockholders' Equity Note [Abstract]	'
Schedule of Share-based Compensation, Nonemployee Director Stock Award Plan, Activity [Table Text Block]	'
		2013		2012		2011
	Annual director fees paid through stock issuance	$	167,946	$	148,437	$	112,493
	Shares of common stock issued		9,885		9,040		6,495
	Dividends paid per common share	$	0.24	$	0.74	$	0.24

Note_9_StockBased_Compensation1

Note 9 - Stock-Based Compensation and Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	'
			Year Ended December 31,
			2013			2012		2011
	Dividend yield (1)			1.54	%	N/A			1.58	%
	Expected volatility (2)			24.92	%	N/A			33.73	%
	Risk-free interest rate (3)			0.34	%	N/A			0.38	%
	Expected terms (years) (4)			2.74		N/A			3.92
	Weighted average fair value of options granted		$	2.25		N/A		$	3.48
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]	'
			2013								2012					2011
			Options				Weighted				Options			Weighted		Options			Weighted
							Average							Average					Average
							Exercise							Exercise					Exercise
							Price							Price					Price
	Outstanding at beginning of year			3,424,806			$	15.99				3,823,585		$	15.8		4,144,476		$	15.68
	Granted			429,800				15.62				-		$	0		109,500		$	15.15
	Exercised			(345,302	)			12.6				(281,993	)	$	12.85		(189,788	)	$	10.53
	Forfeited and Expired			(134,458	)			16.78				(116,786	)	$	17.13		(240,603	)	$	16.72
	Outstanding at end of year			3,374,846				16.26				3,424,806		$	15.99		3,823,585		$	15.8
	Vested and exercisable at end of year			2,828,245				16.27				3,174,843		$	15.86		2,314,558		$	15.32
	Weighted average fair value of options granted during the period							2.25						N/A					$	3.48
Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]	'
		Range of					Shares				Weighted Avg.			Weighted Avg.		Number Vested			Weighted
		Exercise					Outstanding				Contractual			Exercise Price		and Exercisable			Avg. Exercise
		Prices									Years			Per Share					Price Per
											Remaining								Share for
																			Vested and
																			Exercisable
		$8.42	-	10.52				2,610				0.34			$10.37		2,610			$10.37
		$10.53	-	12.63				181,664				0.45			$11.80		181,664			$11.40
		$12.63	-	14.73				160,690				1.42			$14.45		156,790			$14.47
		$14.74	-	16.83				1,702,830				3.08			$15.44		1,271,209			$15.40
		$16.84	-	18.94				1,294,052				3.77			$18.11		1,186,972			$18.04
		$18.95	-	21.05				33,000				2.84			$20.03		29,000			$20.14
		Overall Total						3,374,846				3.12			$16.26		2,828,245			$16.27
Schedule of Nonvested Restricted Stock Units Activity [Table Text Block]	'
			2013								2012					2011
			Number of				Weighted				Number of			Weighted		Number of			Weighted
			Restricted				Average				Restricted			Average		Restricted			Average
			Stock Awards				Grant Date				Stock Awards			Grant Date		Stock Awards			Grant Date
							Fair Value							Fair Value					Fair Value
	Unvested at January 1
	Unvested at January 1,			1,210,532			$	16.04				1,325,817		$	16.01		1,364,560		$	16.11
	Granted			183,111			$	15.95				41,000		$	16.76		123,500		$	15.03
	Vested			(130,265	)		$	16.01				(114,605	)	$	16		(81,513	)	$	16.11
	Forfeited and Expired			(49,680	)		$	15.75				(41,680	)	$	15.97		(80,730	)	$	16.07
	Outstanding (unvested) at end of year			1,213,698			$	16.04				1,210,532		$	16.04		1,325,817		$	16.01

Note_11_Segment_Information_Ta

Note 11 - Segment Information (Tables)	12 Months Ended
	Dec. 31, 2013
Note 11 - Segment Information (Tables) [Line Items]	'
Schedule of Segment Reporting Information, by Segment [Table Text Block]	'
		2013			2012		2011
	Brokerage gross margin percent (1)		13.30%			13.60%		11.70%
	Intermodal gross margin percent(1)		10.70%			12.00%		8.20%
Asset-Based Segment [Member]	'
Note 11 - Segment Information (Tables) [Line Items]	'
Reconciliation of Revenue from Segments to Consolidated [Table Text Block]	'
		2013					2012					2011
	Asset-Based (amounts in thousands)	$			%		$			%		$			%
	Revenue	$	822,188				$	836,357				$	785,989
	Operating expenses		716,021			87.1		733,344			87.7		691,006			87.9
	Operating income	$	106,167				$	103,013				$	94,983
		2013					2012					2011
	Asset-Based (amounts in thousands)	$			%		$			%		$			%
	Revenue	$	822,188				$	836,357				$	785,989
	Less: Asset-Based fuel surcharge revenue		(177,386	)				(183,885	)				(168,913	)
	Less: Intersegment transactions(1)		(120	)				(112	)				(82	)
	Revenue, net of fuel surcharge and intersegment transactions(1)		644,682					652,360					616,994
	Operating expenses		716,021					733,344					691,006
	Less: Asset-Based fuel surcharge revenue		(177,386	)				(183,885	)				(168,913	)
	Less: Intersegment transactions(1)		(120	)				(112	)				(82	)
	Operating expenses, net of fuel surcharge and intersegment transactions(1)		538,515			83.5		549,347			84.2		522,011			84.6
	Operating income	$	106,167				$	103,013				$	94,983
Non-Asset-Based Segment [Member]	'
Note 11 - Segment Information (Tables) [Line Items]	'
Reconciliation of Revenue from Segments to Consolidated [Table Text Block]	'
		2013					2012					2011
	Non-Asset-Based (amounts in thousands)	$			%		$			%		$			%
	Revenue	$	151,194				$	105,794				$	86,449
	Other operating expenses		143,452			94.9		100,540			95		81,411			94.2
	Operating income	$	7,742				$	5,254				$	5,038
		2013					2012					2011
	Non-Asset-Based (amounts in thousands)	$			%		$			%		$			%
	Revenue	$	151,194				$	105,794				$	86,449
	Less: Intersegment transactions		(4,025	)				(6,003	)				(6,157	)
	Revenue excluding intersegment transactions		147,169					99,791					80,292
	Operating expenses		143,452					100,540					81,411
	Less: Intersegment transactions		(4,025	)				(6,003	)				(6,157	)
	Operating expenses excluding intersegment transactions		139,427			94.7		94,537			94.7		75,254			93.7
	Operating income	$	7,742				$	5,254				$	5,038

Note_12_Quarterly_Financial_Da1

Note 12 - Quarterly Financial Data (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Schedule of Quarterly Financial Information [Table Text Block]	'
		2013
		31-Mar		30-Jun		30-Sep		31-Dec
	Revenue, before fuel surcharge		189,600		200,104		195,847		206,300
	Income from operations		25,544		31,925		24,274		32,165
	Net income attributable to Knight		15,183		18,939		15,059		20,101
	Earnings per common share:
	Basic	$	0.19	$	0.24	$	0.19	$	0.25
	Diluted	$	0.19	$	0.24	$	0.19	$	0.25
		2012
		31-Mar		30-Jun		30-Sep		31-Dec
	Revenue, before fuel surcharge	$	175,599	$	188,838	$	192,550	$	195,164
	Income from operations	$	19,834	$	32,103	$	27,767	$	28,564
	Net income attributable to Knight	$	10,546	$	19,289	$	16,584	$	17,698
	Earnings per common share:
	Basic	$	0.13	$	0.24	$	0.21	$	0.22
	Diluted	$	0.13	$	0.24	$	0.21	$	0.22

Note_1_Organization_and_Summar2

Note 1 - Organization and Summary of Significant Accounting Policies (Details) (USD $)

12 Months Ended

12 Months Ended

51 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2003

Dec. 31, 2006

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2008

Dec. 31, 2007

Dec. 31, 2006

Dec. 31, 2013

Dec. 31, 2012

Three Largest Customers [Member]

Three Largest Customers [Member]

Three Largest Customers [Member]

Three Largest Customers [Member]

Three Largest Customers [Member]

Single Largest Customer [Member]

Single Largest Customer [Member]

Single Largest Customer [Member]

Single Largest Customer [Member]

Single Largest Customer [Member]

Transportation Resource Partners [Member]

Transportation Resource Partners [Member]

Transportation Resource Partners [Member]

Transportation Resource Partners [Member]

Transportation Resource Partners [Member]

Transportation Resource Partners III [Member]

Transportation Resource Partners III [Member]

Transportation Resource Partners III [Member]

Transportation Resource Partners III [Member]

Transportation Resource Partners III [Member]

Roads West [Member]

Roads West [Member]

Self-Insurance Program [Member]

Self-Insurance Program [Member]

Accounts Receivable [Member]

Accounts Receivable [Member]

Accounts Receivable [Member]

Accounts Receivable [Member]

Note 1 - Organization and Summary of Significant Accounting Policies (Details) [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of Reportable Segments

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest On Note Receivable Minimum

2.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest On Note Receivable Maximum

20.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Loans Outstanding Independent Contractors

117

126

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Assets Held-for-sale, Long Lived

$16,500,000

$18,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cost of Property Repairs and Maintenance

30,500,000

30,400,000

24,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5,000,000

'

'

'

'

'

'

'

'

'

'

Total Amounts Committed To Partnership

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

260,000,000

'

'

'

'

'

'

'

'

'

'

Joint Venture Ownership Interest

'

'

'

'

'

'

'

'

'

'

'

'

'

1.90%

'

'

1.90%

'

'

'

'

'

'

'

'

'

'

Amounts Committed To Invest

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5,500,000

5,500,000

'

'

'

'

15,000,000

'

'

'

'

Payments to Acquire Interest in Joint Venture

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

142,000

'

'

'

'

'

'

'

'

'

'

'

Gain on Sale of Investments

'

'

'

'

'

'

'

'

'

'

'

'

'

467,000

216,000

115,000

'

'

'

'

'

'

'

'

'

'

'

Other than Temporary Impairment Losses, Investments

209,000

0

'

'

'

'

'

'

'

'

'

'

'

209,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Investments

'

'

'

'

'

'

'

'

'

'

'

'

'

2,000,000

2,200,000

'

'

'

10,800,000

'

'

10,800,000

'

'

'

'

'

Payments for (Proceeds from) Investments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10,800,000

'

'

'

'

'

Remaining Investment Commitment

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4,200,000

'

'

4,200,000

'

'

'

'

'

Income (Loss) from Equity Method Investments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

669,000

261,000

74,000

'

'

'

'

'

'

Equity Method Investments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

11,440,000

7,568,000

'

11,440,000

'

'

'

'

'

Equity Method Investment, Ownership Percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6.10%

'

'

6.10%

'

'

'

'

'

Restricted Cash and Cash Equivalents

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3,600,000

3,900,000

Goodwill, Acquired During Period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,800,000

'

'

Finite Lived Intangible Assets Acquired During Period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

310,000

'

'

Payment Of Earnout

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$135,000

'

'

'

Concentration Risk, Percentage

'

'

'

6.50%

7.70%

11.00%

10.00%

12.00%

1.20%

1.30%

4.00%

4.00%

5.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Note_1_Organization_and_Summar3

Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Current and Long-Term Balance of our Notes Receivable (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current and Long-Term Balance of our Notes Receivable [Abstract]	'	'
Notes receivable from independent contractors	$503	$605
Notes receivable from third parties	4,630	4,169
Gross notes receivable	5,133	4,774
Allowance for doubtful notes receivable	-312	-291
Total notes receivable, net of allowance	4,821	4,483
Current portion, net of allowance	774	791
Long-term portion	$4,047	$3,692

Note_1_Organization_and_Summar4

Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Estimated Useful Lives of Property and Equipment	12 Months Ended
	Dec. 31, 2013
Land Improvements [Member] | Minimum [Member]	'
Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Estimated Useful Lives of Property and Equipment [Line Items]	'
Estimated Useful Lives	'5 years
Land Improvements [Member] | Maximum [Member]	'
Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Estimated Useful Lives of Property and Equipment [Line Items]	'
Estimated Useful Lives	'10 years
Building and Building Improvements [Member] | Minimum [Member]	'
Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Estimated Useful Lives of Property and Equipment [Line Items]	'
Estimated Useful Lives	'15 years
Building and Building Improvements [Member] | Maximum [Member]	'
Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Estimated Useful Lives of Property and Equipment [Line Items]	'
Estimated Useful Lives	'30 years
Furniture and Fixtures [Member] | Minimum [Member]	'
Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Estimated Useful Lives of Property and Equipment [Line Items]	'
Estimated Useful Lives	'3 years
Furniture and Fixtures [Member] | Maximum [Member]	'
Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Estimated Useful Lives of Property and Equipment [Line Items]	'
Estimated Useful Lives	'10 years
Shop and Service Equipment [Member] | Minimum [Member]	'
Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Estimated Useful Lives of Property and Equipment [Line Items]	'
Estimated Useful Lives	'2 years
Shop and Service Equipment [Member] | Maximum [Member]	'
Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Estimated Useful Lives of Property and Equipment [Line Items]	'
Estimated Useful Lives	'5 years
Revenue Equipment [Member] | Minimum [Member]	'
Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Estimated Useful Lives of Property and Equipment [Line Items]	'
Estimated Useful Lives	'5 years
Revenue Equipment [Member] | Maximum [Member]	'
Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Estimated Useful Lives of Property and Equipment [Line Items]	'
Estimated Useful Lives	'10 years
Leasehold Improvements [Member] | Minimum [Member]	'
Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Estimated Useful Lives of Property and Equipment [Line Items]	'
Estimated Useful Lives	'1 year
Leasehold Improvements [Member] | Maximum [Member]	'
Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Estimated Useful Lives of Property and Equipment [Line Items]	'
Estimated Useful Lives	'5 years

Note_1_Organization_and_Summar5

Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Other Long-term Assets and Restricted Cash (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Other Long-term Assets and Restricted Cash [Line Items]	'	'
Restricted Cash and Investments	$3,603	$3,947
Available-For-Sale Equity Securities	17,454	6,369
Other	1,662	1,253
	36,194	21,383
Transportation Resource Partners [Member]	'	'
Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Other Long-term Assets and Restricted Cash [Line Items]	'	'
Investment in Transportation Resource Partners (TRP)	2,035	2,246
Transportation Resource Partners III [Member]	'	'
Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Other Long-term Assets and Restricted Cash [Line Items]	'	'
Investment in Transportation Resource Partners III (TRP III)	$11,440	$7,568

Note_1_Organization_and_Summar6

Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Changes in Carrying Amount of Goodwill (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Changes in Carrying Amount of Goodwill [Abstract]	'	'
Goodwill at beginning of period	$10,276	$10,295
Amortization relating to deferred tax assets	-19	-19
Goodwill at end of period	$10,257	$10,276

Note_1_Organization_and_Summar7

Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Earnings Per Share (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
Earnings Per Share [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Basic EPS (in Dollars)	'	'	'	'	'	'	'	'	$69,282	$64,117	$60,248
Basic EPS	'	'	'	'	'	'	'	'	79,994	79,673	81,439
Basic EPS (in Dollars per share)	$0.25	$0.19	$0.24	$0.19	$0.22	$0.21	$0.24	$0.13	$0.87	$0.80	$0.74
Effect of stock options & restricted stock	'	'	'	'	'	'	'	'	336	327	433
Diluted EPS (in Dollars)	'	'	'	'	'	'	'	'	$69,282	$64,117	$60,248
Diluted EPS	'	'	'	'	'	'	'	'	80,330	80,000	81,872
Diluted EPS (in Dollars per share)	$0.25	$0.19	$0.24	$0.19	$0.22	$0.21	$0.24	$0.13	$0.86	$0.80	$0.74

Note_1_Organization_and_Summar8

Note 1 - Organization and Summary of Significant Accounting Policies (Details) - Anti-dilutive Shares	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Anti-dilutive Shares [Abstract]	'	'	'
Number of anti-dilutive shares	1,917,020	1,926,298	2,655,814

Note_2_Fair_Value_Measurements2

Note 2 - Fair Value Measurements (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Fair Value Disclosures [Abstract]	'	'
Available-for-sale Securities	$17,500,000	'
Available-for-sale Securities, Gross Realized Gains	1,200,000	'
Available-for-sale Securities, Gross Realized Gain (Loss)	700,000	'
Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss) before Taxes	3,700,000	'
Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax	2,300,000	'
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	4,600,000	-302,000
Available-for-sale Securities, Income Tax Expense on Change in Unrealized Holding Gain (Loss)	$2,800,000	$185,000

Note_2_Fair_Value_Measurements3

Note 2 - Fair Value Measurements (Details) - Fair Value of Financial Assets and Liabilities (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Equity securities -	'	'
common shares	$17,454	$6,369
Restricted cash and investments:	'	'
Money market funds	1,371	1,231
municipal securities	2,232	2,716
Fair Value, Inputs, Level 1 [Member]	'	'
Equity securities -	'	'
common shares	17,454	6,369
Restricted cash and investments:	'	'
Money market funds	1,371	1,231
Fair Value, Inputs, Level 2 [Member]	'	'
Restricted cash and investments:	'	'
municipal securities	$2,232	$2,716

Note_3_Line_of_Credit_and_Long1

Note 3 - Line of Credit and Long-Term Debt (Details) (USD $)	2 Months Ended	10 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Oct. 31, 2013	Dec. 31, 2013	Dec. 31, 2012
Note 3 - Line of Credit and Long-Term Debt (Details) [Line Items]	'	'	'	'
NewLineOfCredit	'	$150	'	'
Debt Instrument, Basis Spread on Variable Rate	0.75%	0.63%	'	'
Line of Credit Facility, Maximum Borrowing Capacity	300	'	300	'
Line of Credit Facility, Amount Outstanding	38	'	38	80
Line of Credit Facility, Interest Rate During Period	'	'	1.04%	0.94%
Line of Credit Facility, Remaining Borrowing Capacity	238	'	238	'
Letter of Credit [Member]	'	'	'	'
Note 3 - Line of Credit and Long-Term Debt (Details) [Line Items]	'	'	'	'
Line of Credit, Current	$24	'	$24	'

Note_4_Income_Taxes_Details_In

Note 4 - Income Taxes (Details) - Income Tax Expense (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Expense [Abstract]	'	'	'
Federal	$46,445	$42,280	$6,466
State	5,573	4,709	3,602
	52,018	46,989	10,068
Federal	-5,520	-2,403	30,087
State	182	428	325
	-5,338	-1,975	30,412
	$46,680	$45,014	$40,480

Note_4_Income_Taxes_Details_Ef

Note 4 - Income Taxes (Details) - Effective Income Tax Rate Reconciliation (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Effective Income Tax Rate Reconciliation [Abstract]	'	'	'
Tax at the statutory rate (35%)	$40,846	$38,422	$35,416
State income taxes, net of federal benefit	3,804	3,489	2,667
Nondeductible driver per diem	1,807	1,989	1,984
Other, net	223	1,114	413
	$46,680	$45,014	$40,480

Note_4_Income_Taxes_Details_Ef1

Note 4 - Income Taxes (Details) - Effective Income Tax Rate Reconciliation (Parentheticals)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Effective Income Tax Rate Reconciliation [Abstract]	'	'	'
Statutory rate	35.00%	35.00%	35.00%

Note_4_Income_Taxes_Details_De

Note 4 - Income Taxes (Details) - Deferred Tax Assets and Deferred Tax Liabilities (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Short-term deferred tax assets (liabilities):	'	'
Claims accrual	$2,460	$2,317
Stock options	2,254	2,257
Other	882	1,137
Prepaid expenses deducted for tax purposes	-2,237	-2,302
Short-term deferred tax assets, net	3,359	3,409
Long-term deferred tax liabilities (assets):	'	'
Property and equipment depreciation	143,488	150,525
Claims accrual	-984	-5,654
Long-term deferred liabilities, net	$142,504	$144,871

Note_5_Commitments_and_Conting2

Note 5 - Commitments and Contingencies (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2006	Dec. 31, 2003	Dec. 31, 2013	Dec. 31, 2008
				Transportation Resource Partners [Member]	Transportation Resource Partners [Member]	Transportation Resource Partners [Member]	Transportation Resource Partners [Member]	Transportation Resource Partners III [Member]	Transportation Resource Partners III [Member]
Note 5 - Commitments and Contingencies (Details) [Line Items]	'	'	'	'	'	'	'	'	'
Purchase Commitment, Remaining Minimum Amount Committed	$68.90	$8.50	'	'	'	'	'	'	'
Amounts Committed To Invest	'	'	'	'	'	5.5	5.5	'	15
Investments	'	'	'	2	2.2	'	'	10.8	'
Remaining Investment Commitment	'	'	'	'	'	'	'	4.2	'
Operating Leases, Rent Expense	$2.20	$2.40	$2.50	'	'	'	'	'	'

Note_5_Commitments_and_Conting3

Note 5 - Commitments and Contingencies (Details) - Future Minimum Lease Payments (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Future Minimum Lease Payments [Abstract]	'
2014	$1,429
2015	1,255
2016	1,238
2017	1,272
2018 & thereafter	407
Total	$5,601

Note_6_Claims_Accrual_Details

Note 6 - Claims Accrual (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Note 6 - Claims Accrual (Details) [Line Items]	'	'
Self-Insurance Retention for Workers' Compensation Claims Per Occurrence	$500,000	'
Excess Personal Injury And Property Damage Liability Insurance	105,000,000	'
Self Retention For Employee Medical Health	225,000	225,000
Increase (Decrease) in Self Insurance Reserve	43,797,000	52,140,000
Minimum [Member]	'	'
Note 6 - Claims Accrual (Details) [Line Items]	'	'
Self Insurance Retention	1,000,000	'
Maximum [Member]	'	'
Note 6 - Claims Accrual (Details) [Line Items]	'	'
Self Insurance Retention	3,000,000	'
Current Policy Year [Member]	'	'
Note 6 - Claims Accrual (Details) [Line Items]	'	'
Self Insurance Retention	3,000,000	'
Next Policy Year [Member]	'	'
Note 6 - Claims Accrual (Details) [Line Items]	'	'
Self Insurance Retention	2,500,000	'
Insurance And Claim Expense [Member]	'	'
Note 6 - Claims Accrual (Details) [Line Items]	'	'
Increase (Decrease) in Self Insurance Reserve	29,100,000	32,100,000
Workers' Compensation Expense [Member]	'	'
Note 6 - Claims Accrual (Details) [Line Items]	'	'
Increase (Decrease) in Self Insurance Reserve	5,500,000	6,100,000
Medical Expense [Member]	'	'
Note 6 - Claims Accrual (Details) [Line Items]	'	'
Increase (Decrease) in Self Insurance Reserve	9,200,000	13,900,000
Maximum [Member]	'	'
Note 6 - Claims Accrual (Details) [Line Items]	'	'
Self Insurance Aggregate Losses	$1,500,000	'

Note_6_Claims_Accrual_Details_

Note 6 - Claims Accrual (Details) - Current and Long-term Claim Reserves (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Note 6 - Claims Accrual (Details) - Current and Long-term Claim Reserves [Line Items]	'	'	'
Claim reserves	$24,505	$26,232	$21,568
Current portion	15,616	15,892	'
Long-term portion	8,889	10,340	'
Auto Reserves [Member]	'	'	'
Note 6 - Claims Accrual (Details) - Current and Long-term Claim Reserves [Line Items]	'	'	'
Claim reserves	15,432	15,333	'
Workers' Compensation Reserves [Member]	'	'	'
Note 6 - Claims Accrual (Details) - Current and Long-term Claim Reserves [Line Items]	'	'	'
Claim reserves	6,479	8,887	'
Employee Medical Reserves [Member]	'	'	'
Note 6 - Claims Accrual (Details) - Current and Long-term Claim Reserves [Line Items]	'	'	'
Claim reserves	$2,594	$2,012	'

Note_6_Claims_Accrual_Details_1

Note 6 - Claims Accrual (Details) - Reconciliation of Claim Reserves (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Claim Reserves [Abstract]	'	'
Beginning Balance	$26,232	$21,568
Provisions recorded	43,797	52,140
Claims paid and direct expenses	-45,524	-47,476
Total reserves	$24,505	$26,232

Note_7_Related_Party_Transacti1

Note 7 - Related Party Transactions (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013
			US West Agriculture Exporters LLC [Member]
Note 7 - Related Party Transactions (Details) [Line Items]	'	'	'
Related Party Transaction Percent of Ownership	'	'	33.00%
Related Party Transaction, Due from (to) Related Party, Noncurrent	$748,000	$2,800,000	'

Note_8_Shareholders_Equity_Det

Note 8 - Shareholders' Equity (Details) - Annual Director Fees (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Annual Director Fees [Abstract]	'	'	'
Annual director fees paid through stock issuance (in Dollars)	$167,946	$148,437	$112,493
Shares of common stock issued	9,885	9,040	6,495
Dividends paid per common share (in Dollars per share)	$0.24	$0.74	$0.24

Note_9_StockBased_Compensation2

Note 9 - Stock-Based Compensation and Employee Benefit Plans (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Note 9 - Stock-Based Compensation and Employee Benefit Plans (Details) [Line Items]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares Per Employee (in Shares)	'	650,000	'
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in Shares)	'	4,000,000	'
Share-based Compensation	$2,815,000	$6,317,000	$3,501,000
Allocated Share-based Compensation Expense	'	4,000,000	'
Allocated Share-based Compensation Expense, Net of Tax	'	3,900,000	'
Proceeds from Stock Options Exercised	4,345,000	3,623,000	2,009,000
Excess Tax Benefit from Share-based Compensation, Operating Activities	'	30,000	60,000
Employee Service Share Based Compensation Nonvested Awards Cost Not Yet Recognized	1,200,000	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number (in Shares)	3,330,735	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price (in Dollars per share)	$16.27	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term	'3 years 29 days	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value	7,100,000	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	1,500,000	1,300,000	1,200,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	7,300,000	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	6,000,000	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term	'2 years 259 days	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in Shares)	183,111	41,000	123,500
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in Dollars per share)	$15.95	$16.76	$15.03
Deferred Compensation Arrangement with Individual, Employer Contribution	326,000	266,000	273,000
Restricted Stock Units (RSUs) [Member]	'	'	'
Note 9 - Stock-Based Compensation and Employee Benefit Plans (Details) [Line Items]	'	'	'
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	'4 years 146 days	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in Shares)	183,111	41,000	123,500
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in Dollars per share)	$15.95	$16.76	'
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$15,800,000	'	'
Weighted-Average Period [Member]	'	'	'
Note 9 - Stock-Based Compensation and Employee Benefit Plans (Details) [Line Items]	'	'	'
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	'2 years 36 days	'	'
Total Period [Member]	'	'	'
Note 9 - Stock-Based Compensation and Employee Benefit Plans (Details) [Line Items]	'	'	'
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	'3 years 328 days	'	'
Minimum [Member]	'	'	'
Note 9 - Stock-Based Compensation and Employee Benefit Plans (Details) [Line Items]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in Dollars per share)	'	'	$14.96
Maximum [Member]	'	'	'
Note 9 - Stock-Based Compensation and Employee Benefit Plans (Details) [Line Items]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in Dollars per share)	'	'	$15.15
Reserved For Issuance To Outside Directors [Member]	'	'	'
Note 9 - Stock-Based Compensation and Employee Benefit Plans (Details) [Line Items]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in Shares)	'	200,000	'
Minimum [Member]	'	'	'
Note 9 - Stock-Based Compensation and Employee Benefit Plans (Details) [Line Items]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	'5 years	'	'
Maximum [Member]	'	'	'
Note 9 - Stock-Based Compensation and Employee Benefit Plans (Details) [Line Items]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	'13 years	'	'

Note_9_StockBased_Compensation3

Note 9 - Stock-Based Compensation and Employee Benefit Plans (Details) - Fair Value Assumtions (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Fair Value Assumtions [Abstract]	'		'		'
Dividend yield (1)	1.54%	[1]	'	[1]	1.58%	[1]
Expected volatility (2)	24.92%	[2]	'	[2]	33.73%	[2]
Risk-free interest rate (3)	0.34%	[3]	'	[3]	0.38%	[3]
Expected terms (years) (4)	'2 years 270 days	[4]	'	[4]	'3 years 335 days	[4]
Weighted average fair value of options granted (in Dollars per share)	$2.25		'		$3.48
[1]	The dividend yield is based on the Company's historical experience and future expectation of dividend payouts.
[2]	The Company analyzed the volatility of its stock using historical data for the past seven years to through the end of the most recent period to estimate expected volatility.
[3]	The risk-free interest rate assumption is based on U.S. Treasury securities at a constant maturity with a maturity period that most closely resembles the expected term of the stock option award.
[4]	The expected terms of employee stock options represents the weighted-average period the stock options are expected to remain outstanding and has been determined based on historical exercise behavior for the past seven years through the end of the most recent period.

Note_9_StockBased_Compensation4

Note 9 - Stock-Based Compensation and Employee Benefit Plans (Details) - Option Award Activity Under 2003 Plan (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Option Award Activity Under 2003 Plan [Abstract]	'	'	'
Options (in Shares)	3,424,806	3,823,585	4,144,476
Weighted average exercise price	$15.99	$15.80	$15.68
Vested and exercisable at end of year (in Shares)	2,828,245	3,174,843	2,314,558
Vested and exercisable at end of year	$16.27	$15.86	$15.32
Weighted average fair value of options granted during the period	$2.25	'	$3.48
Granted	$15.62	$0	$15.15
Granted (in Shares)	429,800	'	109,500
Exercised (in Shares)	-345,302	-281,993	-189,788
Exercised	$12.60	$12.85	$10.53
Forfeited and Expired (in Shares)	-134,458	-116,786	-240,603
Forfeited and Expired	$16.78	$17.13	$16.72
Options (in Shares)	3,374,846	3,424,806	3,823,585
Weighted average exercise price	$16.26	$15.99	$15.80

Note_9_StockBased_Compensation5

Note 9 - Stock-Based Compensation and Employee Benefit Plans (Details) - Summary of Stock Option Information (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'	'	'
Shares Outstanding (in Shares)	3,374,846	3,424,806	3,823,585	4,144,476
Weighted Average Contractual Years Remaining	'3 years 43 days	'	'	'
Weighted Average Exercise Price Per Share	$16.26	$15.99	$15.80	$15.68
Number Vested and Exercisable (in Shares)	2,828,245	'	'	'
Weighted Average Exercise Price Per Share for Vested and Exercisable	$16.27	'	'	'
Range 1 [Member]	'	'	'	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'	'	'
Lower Range of Exercise Price	$8.42	'	'	'
Upper Range of Exercise Price	$10.52	'	'	'
Shares Outstanding (in Shares)	2,610	'	'	'
Weighted Average Contractual Years Remaining	'124 days	'	'	'
Weighted Average Exercise Price Per Share	$10.37	'	'	'
Number Vested and Exercisable (in Shares)	2,610	'	'	'
Weighted Average Exercise Price Per Share for Vested and Exercisable	$10.37	'	'	'
Range 2 [Member]	'	'	'	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'	'	'
Lower Range of Exercise Price	$10.53	'	'	'
Upper Range of Exercise Price	$12.63	'	'	'
Shares Outstanding (in Shares)	181,664	'	'	'
Weighted Average Contractual Years Remaining	'164 days	'	'	'
Weighted Average Exercise Price Per Share	$11.80	'	'	'
Number Vested and Exercisable (in Shares)	181,664	'	'	'
Weighted Average Exercise Price Per Share for Vested and Exercisable	$11.40	'	'	'
Range 3 [Member]	'	'	'	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'	'	'
Lower Range of Exercise Price	$12.63	'	'	'
Upper Range of Exercise Price	$14.73	'	'	'
Shares Outstanding (in Shares)	160,690	'	'	'
Weighted Average Contractual Years Remaining	'1 year 153 days	'	'	'
Weighted Average Exercise Price Per Share	$14.45	'	'	'
Number Vested and Exercisable (in Shares)	156,790	'	'	'
Weighted Average Exercise Price Per Share for Vested and Exercisable	$14.47	'	'	'
Range 4 [Member]	'	'	'	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'	'	'
Lower Range of Exercise Price	$14.74	'	'	'
Upper Range of Exercise Price	$16.83	'	'	'
Shares Outstanding (in Shares)	1,702,830	'	'	'
Weighted Average Contractual Years Remaining	'3 years 29 days	'	'	'
Weighted Average Exercise Price Per Share	$15.44	'	'	'
Number Vested and Exercisable (in Shares)	1,271,209	'	'	'
Weighted Average Exercise Price Per Share for Vested and Exercisable	$15.40	'	'	'
Range 5 [Member]	'	'	'	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'	'	'
Lower Range of Exercise Price	$16.84	'	'	'
Upper Range of Exercise Price	$18.94	'	'	'
Shares Outstanding (in Shares)	1,294,052	'	'	'
Weighted Average Contractual Years Remaining	'3 years 281 days	'	'	'
Weighted Average Exercise Price Per Share	$18.11	'	'	'
Number Vested and Exercisable (in Shares)	1,186,972	'	'	'
Weighted Average Exercise Price Per Share for Vested and Exercisable	$18.04	'	'	'
Range 6 [Member]	'	'	'	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'	'	'
Lower Range of Exercise Price	$18.95	'	'	'
Upper Range of Exercise Price	$21.05	'	'	'
Shares Outstanding (in Shares)	33,000	'	'	'
Weighted Average Contractual Years Remaining	'2 years 306 days	'	'	'
Weighted Average Exercise Price Per Share	$20.03	'	'	'
Number Vested and Exercisable (in Shares)	29,000	'	'	'
Weighted Average Exercise Price Per Share for Vested and Exercisable	$20.14	'	'	'

Note_9_StockBased_Compensation6

Note 9 - Stock-Based Compensation and Employee Benefit Plans (Details) - Restricted Stock Unit Award Activity Under 2003 Plan (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restricted Stock Unit Award Activity Under 2003 Plan [Abstract]	'	'	'
Unvested at January 1,	1,210,532	1,325,817	1,364,560
Unvested at January 1, (in Dollars per share)	$16.04	$16.01	$16.11
Granted	183,111	41,000	123,500
Granted (in Dollars per share)	$15.95	$16.76	$15.03
Vested	-130,265	-114,605	-81,513
Vested (in Dollars)	$16.01	$16	$16.11
Forfeited and Expired	-49,680	-41,680	-80,730
Forfeited and Expired (in Dollars per share)	$15.75	$15.97	$16.07
Outstanding (unvested) at end of year	1,213,698	1,210,532	1,325,817
Outstanding (unvested) at end of year (in Dollars per share)	$16.04	$16.04	$16.01

Note_10_Company_Share_Repurcha1

Note 10 - Company Share Repurchase Program (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	19-May-11	Dec. 31, 2010	Nov. 13, 2008
Disclosure Text Block Supplement [Abstract]	'	'	'	'	'	'
Stock Repurchase Program, Number of Shares Authorized to be Repurchased	'	'	'	10,000,000	'	3,000,000
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased	7,438,556	'	'	'	2,020,956	'
Stock Repurchased During Period, Shares	0	0	4,582,400	'	'	'
Stock Repurchased During Period, Value (in Dollars)	'	'	$76,564	'	'	'

Note_11_Segment_Information_De

Note 11 - Segment Information (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Note 11 - Segment Information (Details) [Line Items]	'	'	'
Number of Operating Segments	2	'	'
Depreciation, Depletion and Amortization	$86,129	$85,056	$75,832
Asset-Based Segment [Member]	'	'	'
Note 11 - Segment Information (Details) [Line Items]	'	'	'
Number of Operating Segments	3	'	'
Depreciation, Depletion and Amortization	81,000	79,700	72,500
Non-Asset-Based Segment [Member]	'	'	'
Note 11 - Segment Information (Details) [Line Items]	'	'	'
Number of Operating Segments	2	'	'
Depreciation, Depletion and Amortization	$5,100	$5,300	$3,300

Note_11_Segment_Information_De1

Note 11 - Segment Information (Details) - Reconciliation of Revenue from Segments to Consolidated, Asset-Based (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

Segment Reporting, Revenue Reconciling Item [Line Items]

'

'

'

'

'

'

'

'

'

'

'

Revenue

'

'

'

'

'

'

'

'

$969,237

$936,036

$866,199

Revenue, net of fuel surcharge and intersegment transactions(1)

206,300

195,847

200,104

189,600

195,164

192,550

188,838

175,599

791,851

752,151

697,286

Less: Asset-Based fuel surcharge revenue

'

'

'

'

'

'

'

'

-177,386

-183,885

-168,913

Operating expenses

'

'

'

'

'

'

'

'

855,328

827,769

766,178

Operating income

32,165

24,274

31,925

25,544

28,564

27,767

32,103

19,834

113,909

108,267

100,021

Operating Segments [Member] | Asset-Based Segment [Member]

'

'

'

'

'

'

'

'

'

'

'

Segment Reporting, Revenue Reconciling Item [Line Items]

'

'

'

'

'

'

'

'

'

'

'

Revenue

'

'

'

'

'

'

'

'

822,188

836,357

785,989

Operating expenses, net of fuel surcharge and intersegment transactions(1)

'

'

'

'

'

'

'

'

538,515

[1]

549,347

[1]

522,011

[1]

Operating expenses, net of fuel surcharge and intersegment transactions(1)

'

'

'

'

'

'

'

'

83.50%

[1]

84.20%

[1]

84.60%

[1]

Revenue, net of fuel surcharge and intersegment transactions(1)

'

'

'

'

'

'

'

'

644,682

[1]

652,360

[1]

616,994

[1]

Less: Asset-Based fuel surcharge revenue

'

'

'

'

'

'

'

'

-177,386

-183,885

-168,913

Operating expenses

'

'

'

'

'

'

'

'

716,021

733,344

691,006

Operating expenses

'

'

'

'

'

'

'

'

87.10%

87.70%

87.90%

Operating income

'

'

'

'

'

'

'

'

106,167

103,013

94,983

Asset-Based Segment [Member] | Intersubsegment Eliminations [Member]

'

'

'

'

'

'

'

'

'

'

'

Segment Reporting, Revenue Reconciling Item [Line Items]

'

'

'

'

'

'

'

'

'

'

'

Revenue

'

'

'

'

'

'

'

'

-120

[1]

-112

[1]

-82

[1]

Asset-Based Segment [Member] | Reportable Subsegments [Member]

'

'

'

'

'

'

'

'

'

'

'

Segment Reporting, Revenue Reconciling Item [Line Items]

'

'

'

'

'

'

'

'

'

'

'

Operating income

'

'

'

'

'

'

'

'

$106,167

$103,013

$94,983

[1]

These items represent non-GAAP financial measures and are not substitutes for, and should be considered in addition to, the GAAP financial measures presented in the previous table.

Note_11_Segment_Information_De2

Note 11 - Segment Information (Details) - Reconciliation of Revenue from Segments to Consolidated, Non-Asset-Based (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
Segment Reporting, Revenue Reconciling Item [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Revenue	$206,300	$195,847	$200,104	$189,600	$195,164	$192,550	$188,838	$175,599	$791,851	$752,151	$697,286
Operating expenses	'	'	'	'	'	'	'	'	855,328	827,769	766,178
Operating income	32,165	24,274	31,925	25,544	28,564	27,767	32,103	19,834	113,909	108,267	100,021
Operating Segments [Member] | Non-Asset-Based Segment [Member]	'	'	'	'	'	'	'	'	'	'	'
Segment Reporting, Revenue Reconciling Item [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Revenue	'	'	'	'	'	'	'	'	151,194	105,794	86,449
Operating expenses	'	'	'	'	'	'	'	'	143,452	100,540	81,411
Operating expenses	'	'	'	'	'	'	'	'	94.90%	95.00%	94.20%
Operating income	'	'	'	'	'	'	'	'	7,742	5,254	5,038
Non-Asset-Based Segment [Member] | Intersubsegment Eliminations [Member]	'	'	'	'	'	'	'	'	'	'	'
Segment Reporting, Revenue Reconciling Item [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Revenue	'	'	'	'	'	'	'	'	-4,025	-6,003	-6,157
Non-Asset-Based Segment [Member] | Reportable Subsegments [Member]	'	'	'	'	'	'	'	'	'	'	'
Segment Reporting, Revenue Reconciling Item [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Revenue	'	'	'	'	'	'	'	'	147,169	99,791	80,292
Operating expenses	'	'	'	'	'	'	'	'	139,427	94,537	75,254
Operating expenses	'	'	'	'	'	'	'	'	94.70%	94.70%	93.70%
Operating income	'	'	'	'	'	'	'	'	$7,742	$5,254	$5,038

Note_11_Segment_Information_De3

Note 11 - Segment Information (Details) - Gross Margin Percentage of Segments (Reportable Subsegments [Member])	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Brokerage Unit [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Gross margin percent	13.30%	[1]	13.60%	[1]	11.70%	[1]
Intermodal Unit [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Gross margin percent	10.70%	[1]	12.00%	[1]	8.20%	[1]
[1]	Gross margin percentage is based on revenue net of intersegment elimination.

Note_12_Quarterly_Financial_Da2

Note 12 - Quarterly Financial Data (unaudited) (Details) - Quarterly Financial Information (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 [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Revenue, before fuel surcharge	$206,300	$195,847	$200,104	$189,600	$195,164	$192,550	$188,838	$175,599	$791,851	$752,151	$697,286
Income from operations	32,165	24,274	31,925	25,544	28,564	27,767	32,103	19,834	113,909	108,267	100,021
Net income attributable to Knight	$20,101	$15,059	$18,939	$15,183	$17,698	$16,584	$19,289	$10,546	$69,282	$64,117	$60,248
Basic (in Dollars per share)	$0.25	$0.19	$0.24	$0.19	$0.22	$0.21	$0.24	$0.13	$0.87	$0.80	$0.74
Diluted (in Dollars per share)	$0.25	$0.19	$0.24	$0.19	$0.22	$0.21	$0.24	$0.13	$0.86	$0.80	$0.74

Note_13_Subsequent_Events_Deta

Note 13 - Subsequent Events (Details) (USD $)	12 Months Ended			1 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jan. 31, 2014
				Subsequent Event [Member]
				US West Agriculture Exporters LLC [Member]
Note 13 - Subsequent Events (Details) [Line Items]	'	'	'	'
Proceeds from Related Party Debt	$1,570,000	$54,000	$219,000	$748,452

Schedule_II_Valuation_and_Qual1

Schedule II - Valuation and Qualifying Accounts and Reserves (Details) - Valuation and Qualifying Accounts and Reserves (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Valuation Allowance for Impairment of Recognized Servicing Assets [Line Items]	'	'	'
Provisions	$1,008	$883	$578
Allowance for Trade Receivables [Member]	'	'	'
Valuation Allowance for Impairment of Recognized Servicing Assets [Line Items]	'	'	'
Balance at Beginning of Period	1,917	1,651	2,355
Provisions	952	931	326
Write-offs	-460	-665	-1,030
Balance at End of Period	2,409	1,917	1,651
Allowance for Notes Receivable [Member]	'	'	'
Valuation Allowance for Impairment of Recognized Servicing Assets [Line Items]	'	'	'
Balance at Beginning of Period	291	416	480
Provisions	55	-48	252
Write-offs	-34	-77	-316
Balance at End of Period	$312	$291	$416