Kirby (KEX) 10-K 23 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Feb. 20, 2015	Jun. 30, 2014
Document and Entity Information [Abstract]
Entity Registrant Name	KIRBY CORP
Entity Central Index Key	56047
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$6,543,241,000
Entity Common Stock, Shares Outstanding		55,703,000
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$24,299	$4,022
Accounts receivable:
Trade - less allowance for doubtful accounts of $8,887 ($5,055 in 2013)	417,325	311,549
Other	115,598	43,053
Inventories - net, at lower of average cost or market	192,354	135,887
Prepaid expenses and other current assets	43,016	40,037
Deferred income taxes	10,562	9,458
Total current assets	803,154	544,006
Property and equipment:
Marine transportation equipment	3,495,705	3,170,433
Land, buildings and equipment	221,693	205,460
Property and equipment	3,717,398	3,375,893
Accumulated depreciation	1,127,900	1,005,090
Property and equipment - net	2,589,498	2,370,803
Investment in affiliates	2,539	2,156
Goodwill	591,405	591,405
Other assets	155,313	174,147
Total assets	4,141,909	3,682,517
Current liabilities:
Current portion of long-term debt	116,700	0
Income taxes payable	3,470	2,915
Accounts payable	222,020	177,375
Accrued liabilities:
Interest	5,610	5,494
Insurance premiums and claims	121,989	49,162
Employee compensation	42,056	42,613
Taxes - other than on income	13,694	12,160
Other	17,684	19,572
Deferred revenues	50,804	36,698
Total current liabilities	594,027	345,989
Long-term debt - less current portion	600,000	749,150
Deferred income taxes	595,769	544,110
Other long-term liabilities	87,200	21,115
Total long-term liabilities	1,282,969	1,314,375
Contingencies and commitments
Kirby stockholders' equity:
Common stock, $.10 par value per share. Authorized 120,000,000 shares, issued 59,776,000 in 2014 and 2013	5,978	5,978
Additional paid-in capital	428,475	410,615
Accumulated other comprehensive income - net	-61,037	-16,793
Retained earnings	1,974,146	1,692,140
Treasury stock - at cost, 2,906,000 shares in 2014 and 2,930,000 in 2013	-93,526	-81,254
Total Kirby stockholders' equity	2,254,036	2,010,686
Noncontrolling interests	10,877	11,467
Total equity	2,264,913	2,022,153
Total liabilities and equity	$4,141,909	$3,682,517

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Current assets:
Trade, allowance for doubtful accounts	$8,887	$5,055
Equity:
Common stock, par value per share (in dollars per share)	$0.10	$0.10
Common stock, shares authorized (in shares)	120,000,000	120,000,000
Common stock, shares issued (in shares)	59,776,000	59,776,000
Treasury stock, shares (in shares)	2,906,000	2,930,000

CONSOLIDATED_STATEMENTS_OF_EAR

CONSOLIDATED STATEMENTS OF EARNINGS (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues:
Marine transportation	$1,770,684	$1,713,167	$1,408,893
Diesel engine services	795,634	529,028	703,765
Total revenues	2,566,318	2,242,195	2,112,658
Costs and expenses:
Costs of sales and operating expenses	1,694,882	1,448,805	1,409,662
Selling, general and administrative	210,416	177,766	178,483
Taxes, other than on income	16,677	15,893	14,519
Depreciation and amortization	169,312	164,437	145,147
Loss (gain) on disposition of assets	-781	-888	14
Total costs and expenses	2,090,506	1,806,013	1,747,825
Operating income	475,812	436,182	364,833
Equity in earnings of affiliates	384	348	276
Other income (expense)	-345	20	-198
Interest expense	-21,461	-27,872	-24,385
Earnings before taxes on income	454,390	408,678	340,526
Provision for taxes on income	-169,782	-152,379	-127,907
Net earnings	284,608	256,299	212,619
Less: Net earnings attributable to noncontrolling interests	-2,602	-3,238	-3,181
Net earnings attributable to Kirby	$282,006	$253,061	$209,438
Net earnings per share attributable to Kirby common stockholders:
Basic (in dollars per share)	$4.95	$4.46	$3.75
Diluted (in dollars per share)	$4.93	$4.44	$3.73

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Net earnings	$284,608		$256,299		$212,619
Other comprehensive income (loss), net of taxes:
Pension and postretirement benefits	-44,294		43,274		-10,270
Foreign currency translation adjustments	-35		108		102
Change in fair value of derivative instruments	85		952		5,217
Total other comprehensive income (loss), net of taxes	-44,244	[1]	44,334	[1]	-4,951	[1]
Total comprehensive income, net of taxes	240,364		300,633		207,668
Net earnings attributable to noncontrolling interests	-2,602		-3,238		-3,181
Comprehensive income attributable to Kirby	$237,762		$297,395		$204,487
[1]	(b) Reclassifications to net earnings of derivatives qualifying as effective hedges are recognized in interest expense or costs of sales and operating expenses as appropriate. (See Note 4 Derivative Instruments)

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net earnings	$284,608	$256,299	$212,619
Adjustments to reconcile net earnings to net cash provided by operations:
Depreciation and amortization	169,312	164,437	145,147
Provision (credit) for doubtful accounts	3,577	1,260	-42
Provision for deferred income taxes	77,976	103,056	77,005
Loss (gain) on disposition of assets	-781	-888	14
Equity in earnings of affiliates, net of distributions and contributions	-384	-348	1,874
Amortization of unearned share-based compensation	11,591	11,621	9,796
Amortization of scheduled major maintenance costs	16,409	9,029	3,924
Increase (decrease) in cash flows resulting from changes in:
Accounts receivable	-176,544	2,235	-8,744
Inventory	-56,468	43,275	-46,372
Other assets	-11,783	-47,526	-5,180
Income taxes payable	-4,544	313	-4,347
Accounts payable	44,645	23,088	-10,484
Accrued and other liabilities	81,295	35,181	-49,480
Net cash provided by operating activities	438,909	601,032	325,730
Cash flows from investing activities:
Capital expenditures	-355,144	-253,227	-312,167
Acquisitions of businesses and marine equipment, net of cash acquired	-31,800	-3,643	-380,925
Proceeds from disposition of assets	10,393	33,982	19,651
Net cash used in investing activities	-376,551	-222,888	-673,441
Cash flows from financing activities:
Borrowings (payments) on bank credit facilities, net	75,550	-150,960	97,110
Borrowings on long-term debt	0	225,000	275,000
Payments on long-term debt, net	-108,000	-460,000	-39,005
Return of investment to noncontrolling interests	-3,192	-3,857	-2,728
Proceeds from exercise of stock options	7,519	6,635	8,932
Purchase of treasury stock	-15,321	0	0
Payment of contingent liability	-4,756	-5,000	0
Excess tax benefit from equity compensation plans	6,119	3,001	3,212
Net cash provided by (used in) financing activities	-42,081	-385,181	342,521
Increase (decrease) in cash and cash equivalents	20,277	-7,037	-5,190
Cash and cash equivalents, beginning of year	4,022	11,059	16,249
Cash and cash equivalents, end of year	24,299	4,022	11,059
Cash paid during the year:
Interest	19,622	21,393	21,364
Income taxes	90,460	46,136	52,105
Noncash investing activity:
Stock issued in acquisitions	0	0	29,080
Cash acquired in acquisitions	$0	$0	$2,301

CONSOLIDATED_STATEMENTS_OF_STO

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $)	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Noncontrolling Interests [Member]	Total
Balance at beginning of year at Dec. 31, 2011	$5,928,000	$357,294,000	($56,176,000)	$1,229,641,000	($94,162,000)	$11,633,000
Issuance of shares in acquisition	50,000	29,030,000
Excess of proceeds received upon exercise of stock options and issuance of restricted stock over cost of treasury stock issued		6,716,000
Tax benefit realized from equity compensation plans		3,212,000					3,212,000
Issuance of restricted stock, net of forfeitures		-8,263,000
Amortization of unearned compensation		9,796,000
Net earnings attributable to Kirby for the year				209,438,000			209,438,000
Purchase of treasury stock (187,000 in 2014)					0
Cost of treasury stock issued upon exercise of stock options and issuance of restricted stock (211,000 in 2014, 261,000 in 2013 and 341,000 in 2012)					7,415,000
Net earnings attributable to noncontrolling interests						3,181,000	-3,181,000
Return of investment to noncontrolling interests						-2,728,000	2,728,000
Other comprehensive income (loss), net of taxes			-4,951,000				-4,951,000	[1]
Balance at end of year at Dec. 31, 2012	5,978,000	397,785,000	-61,127,000	1,439,079,000	-86,747,000	12,086,000
Issuance of shares in acquisition	0	0
Excess of proceeds received upon exercise of stock options and issuance of restricted stock over cost of treasury stock issued		8,276,000
Tax benefit realized from equity compensation plans		3,001,000					3,001,000
Issuance of restricted stock, net of forfeitures		-10,068,000
Amortization of unearned compensation		11,621,000
Net earnings attributable to Kirby for the year				253,061,000			253,061,000
Purchase of treasury stock (187,000 in 2014)					0
Cost of treasury stock issued upon exercise of stock options and issuance of restricted stock (211,000 in 2014, 261,000 in 2013 and 341,000 in 2012)					5,493,000
Net earnings attributable to noncontrolling interests						3,238,000	-3,238,000
Return of investment to noncontrolling interests						-3,857,000	3,857,000
Other comprehensive income (loss), net of taxes			44,334,000				44,334,000	[1]
Balance at end of year at Dec. 31, 2013	5,978,000	410,615,000	-16,793,000	1,692,140,000	-81,254,000	11,467,000	2,022,153,000
Issuance of shares in acquisition	0	0
Excess of proceeds received upon exercise of stock options and issuance of restricted stock over cost of treasury stock issued		8,345,000
Tax benefit realized from equity compensation plans		6,119,000					6,119,000
Issuance of restricted stock, net of forfeitures		-8,195,000
Amortization of unearned compensation		11,591,000
Net earnings attributable to Kirby for the year				282,006,000			282,006,000
Purchase of treasury stock (187,000 in 2014)					-15,321,000
Cost of treasury stock issued upon exercise of stock options and issuance of restricted stock (211,000 in 2014, 261,000 in 2013 and 341,000 in 2012)					3,049,000
Net earnings attributable to noncontrolling interests						2,602,000	-2,602,000
Return of investment to noncontrolling interests						-3,192,000	3,192,000
Other comprehensive income (loss), net of taxes			-44,244,000				-44,244,000	[1]
Balance at end of year at Dec. 31, 2014	$5,978,000	$428,475,000	($61,037,000)	$1,974,146,000	($93,526,000)	$10,877,000	$2,264,913,000
[1]	(b) Reclassifications to net earnings of derivatives qualifying as effective hedges are recognized in interest expense or costs of sales and operating expenses as appropriate. (See Note 4 Derivative Instruments)

CONSOLIDATED_STATEMENTS_OF_STO1

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY [Abstract]
Purchase of treasury stock (in shares)	187,000
Cost of treasury stock issued upon exercise of stock options and issuance of restricted stock	$211,000	$261,000	$341,000

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Summary of Significant Accounting Policies [Abstract]
Summary of Significant Accounting Policies	(1) Summary of Significant Accounting Policies
	Principles of Consolidation. The consolidated financial statements include the accounts of Kirby Corporation and all majority-owned subsidiaries (“the Company”). Two affiliated limited partnerships, in which the Company owns a 50% interest, is the general partner and has effective control and whose activities are an integral part of the operations of the Company, are consolidated. All other investments in which the Company owns 20% to 50% and exercises significant influence over operating and financial policies are accounted for using the equity method. All material intercompany accounts and transactions have been eliminated in consolidation. Certain reclassifications have been made to reflect the current presentation of financial information.
	Accounting Policies
	Cash Equivalents. Cash equivalents consist of all short-term, highly liquid investments with maturities of three months or less at date of purchase.
	Accounts Receivable. In the normal course of business, the Company extends credit to its customers. The Company regularly reviews the accounts and makes adequate provisions for probable uncollectible balances. It is the Company’s opinion that the accounts have no impairment, other than that for which provisions have been made. Included in accounts receivable as of December 31, 2014 and 2013 were $143,615,000 and $69,481,000, respectively, of accruals for revenues earned which have not been invoiced as of the end of each year.
	The Company’s marine transportation and diesel engine services operations are subject to hazards associated with such businesses. The Company maintains insurance coverage against these hazards with insurance companies. Included in accounts receivable as of December 31, 2014 and 2013 were $92,379,000 and $22,396,000, respectively, of receivables from insurance companies to cover claims in excess of the Company’s deductible.
	Concentrations of Credit Risk. Financial instruments which potentially subject the Company to concentrations of credit risk are primarily trade accounts receivables. The Company’s marine transportation customers include the major oil refining and petrochemical companies. The diesel engine services customers are oil and gas service companies, marine transportation companies, commercial fishing companies, power generation companies, and the United States government. The Company regularly reviews its accounts and estimates the amount of uncollectible receivables each period and establishes an allowance for uncollectible amounts. The amount of the allowance is based on the age of unpaid amounts, information about the current financial strength of customers, and other relevant information. Estimates of uncollectible amounts are revised each period, and changes are recorded in the period they become known.
	Fair Value of Financial Instruments. Cash, accounts receivable, accounts payable and accrued liabilities have carrying values that approximate fair value due to the short-term maturity of these financial instruments. The fair value of the Company’s debt instruments is more fully described in Note 5, Long-Term Debt.
	Property, Maintenance and Repairs. Property is recorded at cost. Improvements and betterments are capitalized as incurred. Depreciation is recorded on the straight-line method over the estimated useful lives of the individual assets as follows: marine transportation equipment, 5-40 years; buildings, 10-40 years; other equipment, 2-10 years; and leasehold improvements, term of lease. When property items are retired, sold or otherwise disposed of, the related cost and accumulated depreciation are removed from the accounts with any gain or loss on the disposition included in the statement of earnings. Maintenance and repairs on vessels built for use on the inland waterways are charged to operating expense as incurred and includes the costs incurred in United States Coast Guard (“USCG”) inspections unless the shipyard extends the life or improves the operating capacity of the vessel which results in the costs being capitalized.
	Drydocking on Ocean-Going Vessels. The Company’s ocean-going vessels are subject to regulatory drydocking requirements after certain periods of time to be inspected, have planned major maintenance performed and be recertified by the American Bureau of Shipping (“ABS”). These recertifications generally occur twice in a five year period. The Company defers the drydocking expenditures incurred on its ocean-going vessels due to regulatory marine inspections by the ABS and amortizes the costs of the shipyard over the period between drydockings, generally 30 or 60 months, depending on the type of major maintenance performed. Drydocking expenditures that extend the life or improve the operating capability of the vessel result in the costs being capitalized. The Company recognized amortization of capitalized planned major maintenance costs of $16,409,000, $9,029,000 and $3,924,000 for the years ended December 31, 2014, 2013 and 2012, respectively, in costs of sales and operating expenses. Routine repairs and maintenance on ocean-going vessels are expensed as incurred. Interest is capitalized on the construction of new ocean-going vessels. Interest expense excludes capitalized interest of $639,000 for the year ending December 31, 2014. No interest was capitalized for the years ending December 31, 2013 and 2012.
	Environmental Liabilities. The Company expenses costs related to environmental events as they are incurred or when a loss is considered probable and estimable.
	Goodwill. The excess of the purchase price over the fair value of identifiable net assets acquired in transactions accounted for as a purchase is included in goodwill. The Company conducted its annual goodwill impairment test at November 30, 2014 and 2013. For 2014 and 2013, the Company noted no impairment of goodwill. The Company will continue to conduct goodwill impairment tests as of November 30 of subsequent years, or whenever events or circumstances indicate that interim impairment testing is necessary. The gross carrying value of goodwill at December 31, 2014 and 2013 was $608,872,000 and accumulated amortization at December 31, 2014 and 2013 was $15,566,000. Accumulated impairment losses were $1,901,000 at December 31, 2014 and 2013.
	Net goodwill for the marine transportation segment was $381,243,000 at December 31, 2014 and 2013. Net goodwill for the diesel engine services segment was $210,162,000 at December 31, 2014 and 2013.
	Revenue Recognition. The majority of marine transportation revenue is derived from term contracts, ranging from one to five years, some of which have renewal options, and the remainder is from spot market movements. The majority of the term contracts are for terms of one year. The Company is a provider of marine transportation services for its customers and, in almost all cases, does not assume ownership of the products it transports. A term contract is an agreement with a specific customer to transport cargo from a designated origin to a designated destination at a set rate or at a daily rate. The rate may or may not escalate during the term of the contract, however, the base rate generally remains constant and contracts often include escalation provisions to recover changes in specific costs such as fuel. A spot contract is an agreement with a customer to move cargo from a specific origin to a designated destination for a rate negotiated at the time the cargo movement takes place. Spot contract rates are at the current “market” rate, including fuel, and are subject to market volatility. The Company uses a voyage accounting method of revenue recognition for its marine transportation revenues which allocates voyage revenue based on the percent of the voyage completed during the period. There is no difference in the recognition of revenue between a term contract and a spot contract.
	Diesel engine service products and services are generally sold based upon purchase orders or preferential service agreements with the customer that include fixed or determinable prices and that do not include right of return or significant post-delivery performance obligations. Diesel engine parts sales are recognized when title passes upon shipment to customers or when customer-specific acceptance requirements are met. Service revenue is recognized as the service is provided. Diesel manufacturing and assembly projects revenue is reported on the percentage of completion method of accounting using measurements of progress towards completion appropriate for the work performed.
	Stock-Based Compensation. The Company has share-based compensation plans covering selected officers and other key employees as well as the Company’s Board of Directors. Stock-based grants made under the Company’s stock plans are recorded at fair value on the date of the grant and the cost is recognized ratably over the vesting period of the stock option or restricted stock. Stock option grants are valued at the date of grant as calculated under the Black-Scholes option pricing model. The Company’s stock-based compensation plans are more fully described in Note 8, Stock Award Plans.
	Taxes on Income. The Company follows the asset and liability method of accounting for income taxes. Under the asset and liability method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date.
	Accrued Insurance. Accrued insurance liabilities include estimates based on individual incurred claims outstanding and an estimated amount for losses incurred but not reported (“IBNR”) or fully developed based on past experience. Insurance premiums, IBNR losses and incurred claim losses, in excess of the Company’s deductible for 2014, 2013 and 2012 were $25,416,000, $22,971,000 and $17,876,000, respectively.
	Noncontrolling Interests. The Company has a majority interest in and is the general partner in several affiliated entities. In situations where losses applicable to the minority interest in the affiliated entities exceed the limited partners’ equity capital, such excess and any further loss attributable to the minority interest is charged against the Company’s interest in the affiliated entities. If future earnings materialize in the respective affiliated entities, the Company’s interest would be credited to the extent of any losses previously absorbed.
	Treasury Stock. The Company follows the average cost method of accounting for treasury stock transactions.
	Impairment of Long-Lived Assets and for Long-Lived Assets to Be Disposed Of. The Company reviews long-lived assets and certain identifiable intangibles for impairment by vessel class whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable.
	Recoverability on marine transportation assets is assessed based on vessel classes, not on individual assets, because identifiable cash flows for individual marine transportation assets are not available. Projecting customer contract volumes allows estimation of future cash flows by projecting pricing and utilization by vessel class but it is not practical to project which individual marine transportation asset will be utilized for any given contract. Because customers do not specify which particular vessel is used, prices are quoted based on vessel classes not individual assets. Nominations of vessels for specific jobs are determined on a day by day basis and are a function of the equipment class required and the geographic position of vessels within that class at that particular time as vessels within a class are interchangeable and provide the same service. The Company’s vessels are mobile assets and equipped to operate in geographic regions throughout the United States and the Company has in the past and expects to continue to move vessels from one region to another when it is necessary due to changing markets and it is economical to do so. Barge vessel classes are based on similar capacities, hull type, and type of product and towing vessels are based on similar hull type and horsepower. Recoverability of the vessel classes is measured by a comparison of the carrying amount of the assets to future net cash flows expected to be generated by the assets. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. Assets to be disposed of are reported at the lower of the carrying amount or fair value less costs to sell.
	Accounting Standards
	In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers” (“ASU 2014-09”). ASU 2014-09 requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. ASU 2014-09 will replace most existing revenue recognition guidance in United States Generally Accepted Accounting Principles when it becomes effective. ASU 2014-09 is effective for the Company on January 1, 2017. Early application is not permitted. ASU 2014-09 permits the use of either the retrospective or cumulative effect transition method. The Company is evaluating the effect that ASU 2014-09 will have on its consolidated financial statements and related disclosures. The Company has not yet selected a transition method nor has it determined the effect of ASU 2014-09 on its ongoing financial reporting.
	In February 2013, the FASB issued ASU 2013-02, “Comprehensive Income (Topic 220): Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income” (“ASU 2013-02”). ASU 2013-02 established the effective date for the requirement to present components of reclassifications out of accumulated other comprehensive income (“OCI”) on the face of the financial statements. The adoption of ASU 2013-02 in the first quarter of 2013 did not have an impact on the Company’s consolidated financial statements except the Company has applied these provisions to its presentation of consolidated financial statements.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2014
Inventories [Abstract]
Inventories	(2) Inventories
	The following table presents the details of inventories as of December 31, 2014 and 2013 (in thousands):
		December 31,		December 31,
		2014		2013
	Finished goods	$	179,760	$	120,751
	Work in process		12,594		15,136
		$	192,354	$	135,887

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2014
Fair Value Measurements [Abstract]
Fair Value Measurements	(3) Fair Value Measurements
	The accounting guidance for using fair value to measure certain assets and liabilities establishes a three tier value hierarchy, which prioritizes the inputs to valuation techniques used in measuring fair value. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets for identical assets or liabilities; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little, if any, market data exists, therefore requiring an entity to develop its own assumptions about the assumptions that market participants would use in pricing the asset or liability.
	The following table summarizes the assets and liabilities measured at fair value on a recurring basis at December 31, 2013 (in thousands):
		Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Total Fair Value Measurements
		(Level 1)		(Level 2)		(Level 3)
	December 31, 2013:
	Assets:
	Derivatives	$	—	$	—	$	—	$	—
	Liabilities:
	Derivatives	$	—	$	59	$	—	$	59
	Contingent liabilities		—		—		4,903		4,903
		$	—	$	59	$	4,903	$	4,962
	In connection with the acquisition of Allied Transportation Company (“Allied”) on November 1, 2012, Allied’s former owners were eligible to receive up to an additional $10,000,000 payable in 2013 through 2015, contingent on developments with the sugar provisions in the United States Farm Bill. The fair value of the contingent liability recorded at the acquisition date was $9,756,000. The fair value of the contingent liability was based on a valuation of the estimated fair value of the liability after probability weighting and discounting various potential payments. Payments of $5,000,000 were made in the 2014 and 2013 first quarters on the contingent liability. The increase in the fair value of the contingent liability of $97,000 and $136,000 for the years ended December 31, 2014 and 2013, respectively, was charged to selling, general and administrative expense. As of December 31, 2014, no Allied contingent liability was recorded and no further payments will be made.
	In connection with the acquisition of United Holdings LLC (“United”) on April 15, 2011, United’s former owners were eligible to receive a three-year earnout provision for up to an additional $50,000,000 payable in 2014, dependent on achieving certain financial targets. The fair value of the contingent earnout liability recorded at the acquisition date was $16,300,000. The fair value of the earnout was based on a valuation of the estimated fair value of the liability after probability weighting and discounting various potential payments. The decrease in the fair value of the earnout liability of $18,300,000 for the year ended December 30, 2013 was credited to selling, general and administrative expense. No United earnout liability was recorded as of December 31, 2013 and December 31, 2014.
	Cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities have carrying values that approximate fair value due to the short-term maturity of these financial instruments. The fair value of the Company’s debt instruments is described in Note 5, Long-Term Debt.
	Certain assets are measured at fair value on a nonrecurring basis and therefore are not included in the table above. These assets are adjusted to fair value when there is evidence of impairment. During the years ended December 31, 2014 and 2013, there was no indication that the Company’s long-lived assets were impaired, and accordingly, measurement at fair value was not required.

Derivative_Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2014
Derivative Instruments [Abstract]
Derivative Instruments	(4) Derivative Instruments
	The Company recognizes all derivative instruments at fair value in the balance sheet as either assets or liabilities. The accounting for changes in the fair value of a derivative instrument depends on the intended use of the derivative and the resulting designation, which is established at the inception date of a derivative. For derivative instruments designated as cash flow hedges, changes in fair value, to the extent the hedge is effective, are recognized in OCI until the hedged item is recognized in earnings. Hedge effectiveness is measured at least quarterly based on the cumulative difference between the fair value of the derivative contract and the hedged item over time. Any change in fair value resulting from ineffectiveness is recognized immediately in earnings.
	Interest Rate Risk Management
	From time to time, the Company has utilized derivative financial instruments with respect to a portion of its interest rate risks to achieve a more predictable cash flow by reducing its exposure to interest rate fluctuations. These transactions generally are interest rate swap agreements and are entered into with large multinational banks. On February 28, 2013, all of the Company’s outstanding interest rate swaps expired. These interest rate swaps, with a total notional amount of $200,000,000, were designated as cash flow hedges.
	Foreign Currency Risk Management
	From time to time, the Company has utilized derivative financial instruments with respect to its forecasted foreign currency transactions to attempt to reduce the risk of its exposure to foreign currency rate fluctuations in its transactions denominated in foreign currency. These transactions, which relate to foreign currency obligations for the purchase of equipment from foreign suppliers or foreign currency receipts from foreign customers, generally are forward contracts or purchased call options and are entered into with large multinational banks. During the 2014 first quarter, the Company’s remaining forward contract with a notional amount of $469,000 expired.
	Fair Value of Derivative Instruments
	The following table sets forth the fair value of the Company’s derivative instruments recorded as liabilities located on the consolidated balance sheet at December 31, 2014 and 2013 (in thousands):
	Liability Derivatives	Balance Sheet Location	2014		2013
	Derivatives designated as hedging instruments under ASC 815:
	Foreign currency contracts	Other accrued liabilities	$	—	$	59
	Foreign currency contracts	Other long-term liabilities		—		—
	Interest rate contracts	Other accrued liabilities		—		—
	Total derivatives designated as hedging instruments under ASC 815		$	—	$	59
	Total liability derivatives		$	—	$	59
	Fair value amounts were derived as of December 31, 2014 and 2013 utilizing fair value models of the Company and its counterparties on the Company’s portfolio of derivative instruments. These fair value models use the income approach that relies on inputs such as yield curves, currency exchange rates and forward prices. The fair value of the Company’s derivative instruments is described above in Note 3, Fair Value Measurements.
	Cash Flow Hedges
	For derivative instruments that are designated and qualify as cash flow hedges, the effective portion of the gain or loss on the derivative is reported as a component of OCI and reclassified into earnings in the same period or periods during which the hedged transaction affects earnings. Gains and losses on the derivative representing either hedge ineffectiveness or hedge components excluded from the assessment of effectiveness are recognized in current earnings. Any ineffectiveness related to the Company’s hedges was not material for any of the periods presented.
	The following table sets forth the location and amount of gains and losses on the Company’s derivative instruments in the consolidated statements of earnings for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Location of Gain (Loss) Reclassified from Accumulated OCI into	Amount of Gain (Loss) Recognized in OCI on Derivatives
			(Effective Portion)
	Derivatives in ASC 815 Cash	Income
	Flow Hedging Relationships:	(Effective Portion)	2014		2013			2012
	Interest rate contracts	Interest expense	$	—	$	1,486		$	7,716
	Foreign exchange contracts	Cost of sales and operating expenses		145		(23	)		346
	Total		$	145	$	1,463		$	8,062
	Derivatives in ASC 815 Cash	Location of Gain (Loss) Reclassified from Accumulated OCI into Income	Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)
	Flow Hedging Relationships:	(Effective Portion)	2014		2013			2012
	Interest rate contracts	Interest expense	$	—	$	(1,389	)	$	(8,321	)
	Foreign exchange contracts	Cost of sales and operating expenses		121		—			19
	Total		$	121	$	(1,389	)	$	(8,302	)

LongTerm_Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2014
Long-Term Debt [Abstract]
Long-Term Debt	(5) Long-Term Debt
	Long-term debt at December 31, 2014 and 2013 consisted of the following (in thousands):
		2014		2013
	Long-term debt, including current portion:
	$150,000,000 senior notes Series A due February 27, 2020	$	150,000	$	150,000
	$350,000,000 senior notes Series B due February 27, 2023		350,000		350,000
	$540,000,000 term loan due July 1, 2016		100,000		208,000
	$325,000,000 revolving credit facility due November 9, 2015		116,700		41,150
	$10,000,000 credit line due June 29, 2015		—		—
		$	716,700	$	749,150
	The aggregate payments due on the long-term debt in each of the next five years were as follows (in thousands):
	2015	$	116,700
	2016		100,000
	2017		—
	2018		—
	2019		—
	Thereafter		500,000
		$	716,700
	The Company has $500,000,000 of unsecured senior notes (“Senior Notes Series A” and “Senior Notes Series B”) with a group of institutional investors, consisting of $150,000,000 of 2.72% Senior Notes Series A due February 27, 2020 and $350,000,000 of 3.29% Senior Notes Series B due February 27, 2023. The Company issued $82,500,000 of Senior Notes Series A and $192,500,000 of Senior Notes Series B on December 13, 2012, the proceeds of which were used to fund the acquisition of Penn Maritime, Inc. (“Penn”). The Company issued $67,500,000 of Senior Notes Series A and $157,500,000 of Senior Notes Series B on February 27, 2013, the proceeds of which were used to refinance $200,000,000 of floating rate senior notes due February 28, 2013, with the balance used to pay down the Company’s unsecured revolving credit facility. No principal payments are required until maturity. The Senior Notes Series A and Series B contain certain covenants on the part of the Company, including an interest coverage covenant, a debt-to-capitalization covenant and covenants relating to liens, asset sales and mergers, among others. The Senior Notes Series A and Series B also specify certain events of default, upon the occurrence of which the maturity of the notes may be accelerated, including failure to pay principal and interest, violation of covenants or default on other indebtedness, among others. As of December 31, 2014, the Company was in compliance with all Senior Notes Series A and Series B covenants and had $150,000,000 of Senior Notes Series A outstanding and $350,000,000 of Senior Notes Series B outstanding.
	The Company has a $325,000,000 unsecured revolving credit facility (“Revolving Credit Facility”) with a syndicate of banks, with JPMorgan Chase Bank, N.A. as the administrative agent bank, with a maturity date of November 9, 2015. The variable interest rate spread varies with the Company’s senior debt rating and is currently 1.5% over the London Interbank Offered Rate (“LIBOR”) or 0.5% over an alternate base rate calculated with reference to the agent bank’s prime rate, among other factors (“Alternate Base Rate”). The commitment fee is currently 0.3%. The Revolving Credit Facility contains certain restrictive financial covenants including an interest coverage ratio and a debt-to-capitalization ratio. In addition to financial covenants, the Revolving Credit Facility contains covenants that, subject to exceptions, restrict debt incurrence, mergers and acquisitions, sales of assets, dividends and investments, liquidations and dissolutions, capital leases, transactions with affiliates and changes in lines of business. Borrowings under the Revolving Credit Facility may be used for general corporate purposes, the purchase of existing or new equipment, the purchase of the Company’s common stock, or for business acquisitions. As of December 31, 2014, the Company was in compliance with all Revolving Credit Facility covenants and had $116,700,000 outstanding under the Revolving Credit Facility which was classified as current portion of long-term debt. The average borrowing under the Revolving Credit Facility during 2014 was $28,591,000, computing by averaging the daily balance, and the weighted average interest rate was 1.7%, computed by dividing the interest expense under the Revolving Credit Facility by the average Revolving Credit Facility borrowing. The Revolving Credit Facility includes a $25,000,000 commitment which may be used for standby letters of credit. Outstanding letters of credit under the Revolving Credit Facility were $4,939,000 as of December 31, 2014.
	The Company has a credit agreement (“Term Loan”) with a group of commercial banks, with Wells Fargo Bank, National Association as the administrative agent bank, with a maturity date of July 1, 2016. The Term Loan provides for a $540,000,000 five-year unsecured term loan facility with a variable interest rate based on LIBOR or an Alternate Base Rate. The interest rate spread varies with the Company’s senior debt rating and is currently 1.5% over LIBOR or 0.5% over the Alternate Base Rate. The outstanding balance of the Term Loan is subject to quarterly amortization in increasing amounts and is prepayable, in whole or in part, without penalty. The Term Loan contains certain restrictive financial covenants including an interest coverage ratio and a debt-to-capitalization ratio. In addition to financial covenants, the Term Loan contains covenants that, subject to exceptions, restrict debt incurrence, mergers and acquisitions, sales of assets, dividends and investments, liquidations and dissolutions, capital leases, transactions with affiliates and changes in lines of business. As of December 31, 2014, the Company was in compliance with all Term Loan covenants and had $100,000,000 outstanding under the Term Loan, none of which was classified as current portion of long-term debt. The average borrowing under the Term Loan during 2014 was $152,892,000, computed by averaging the daily balance, and the weighted average interest rate was 1.7%, computed by dividing the interest expense under the Term Loan by the average Term Loan borrowing.
	The Company had $200,000,000 of unsecured floating rate senior notes (“Senior Notes”) that were retired on February 28, 2013, the maturity date of the Senior Notes, with the proceeds from the Senior Notes Series A and Senior Notes Series B described above.
	The Company has a $10,000,000 line of credit (“Credit Line”) with Bank of America, N.A. (“Bank of America”) for short-term liquidity needs and letters of credit, with a maturity date of June 29, 2015. The Credit Line allows the Company to borrow at an interest rate agreed to by Bank of America and the Company at the time each borrowing is made or continued. The Company had no borrowings outstanding under the Credit Line as of December 31, 2014. Outstanding letters of credit under the Credit Line were $1,194,000 as of December 31, 2014.
	The estimated fair value of total debt outstanding at December 31, 2014 and 2013 was $705,215,000 and $710,377,000, respectively, which differs from the carrying amount of $716,700,000 and $749,150,000, respectively, included in the consolidated financial statements. The fair value was determined using an income approach that relies on inputs such as yield curves.

Taxes_on_Income

Taxes on Income	12 Months Ended
	Dec. 31, 2014
Taxes on Income [Abstract]
Taxes on Income	(6) Taxes on Income
	Earnings before taxes on income and details of the provision for taxes on income for the years ended December 31, 2014, 2013 and 2012 were as follows (in thousands):
		2014			2013			2012
	Earnings before taxes on income — United States	$	454,390		$	408,678		$	340,526
	Provision for taxes on income:
	Federal:
	Current	$	81,953		$	41,008		$	41,297
	Deferred		72,920			97,586			71,767
	State and local		14,909			13,785			14,843
		$	169,782		$	152,379		$	127,907
	During the three years ended December 31, 2014, 2013 and 2012, tax benefits related to the exercise of stock options and the issuance of restricted stock that were allocated directly to additional paid-in capital were $6,119,000, $3,001,000 and $3,212,000, respectively.
	The Company’s provision for taxes on income varied from the statutory federal income tax rate for the years ended December 31, 2014, 2013 and 2012 due to the following:
		2014			2013			2012
	United States income tax statutory rate		35	%		35	%		35	%
	State and local taxes, net of federal benefit		2.2			2.2			2.8
	Other – net		0.2			0.1			(.2	)
			37.4	%		37.3	%		37.6	%
	The tax effects of temporary differences that give rise to significant portions of the current deferred tax assets and non-current deferred tax assets and liabilities at December 31, 2014 and 2013 were as follows (in thousands):
		2014			2013
	Current deferred tax assets:
	Compensated absences	$	854		$	782
	Allowance for doubtful accounts		3,111			1,927
	Insurance accruals		2,858			2,572
	Other		3,739			4,177
		$	10,562		$	9,458
	Non-current deferred tax assets and liabilities:
	Deferred tax assets:
	Postretirement health care benefits	$	2,795		$	3,015
	Insurance accruals		3,325			2,781
	Deferred compensation		10,157			9,526
	Unrealized loss on derivative financial instruments		—			51
	Unrealized loss on defined benefit plans		34,501			9,379
	Operating loss carryforwards		515			5,699
	Other		20,687			17,925
			71,980			48,376
	Deferred tax liabilities:
	Property		(547,388	)		(487,187	)
	Deferred state taxes		(49,503	)		(46,798	)
	Pension benefits		(11,198	)		(13,063	)
	Goodwill and other intangibles		(37,936	)		(26,120	)
	Other		(21,724	)		(19,318	)
			(667,749	)		(592,486	)
		$	(595,769	)	$	(544,110	)
	The Company has determined that it is more likely than not that all deferred tax assets at December 31, 2014 will be realized, including its operating loss carryforwards of $515,000 that expire in various amounts through 2030.
	The Company or one of its subsidiaries files income tax returns in the United States federal jurisdiction and various state jurisdictions. The Company is currently open to audit under the statute of limitations by the Internal Revenue Service for the 2011 through 2013 tax years. With few exceptions, the Company and its subsidiaries’ state income tax returns are open to audit under the statute of limitations for the 2008 through 2013 tax years.
	As of December 31, 2014, the Company has provided a liability of $1,477,000 for unrecognized tax benefits related to various income tax issues which includes interest and penalties. The amount that would impact the Company’s effective tax rate, if recognized, is $998,000, with the difference between the total amount of unrecognized tax benefits and the amount that would impact the effective tax rate being primarily related to the federal tax benefit of state income tax items. It is not reasonably possible to determine if the liability for unrecognized tax benefits will significantly change prior to December 31, 2015 due to the uncertainty of possible examination results.
	A reconciliation of the beginning and ending amount of the liability for unrecognized tax benefits for the years ended December 31, 2014, 2013 and 2012, is as follows (in thousands):
		2014			2013			2012
	Balance at beginning of year	$	949		$	1,045		$	1,532
	Additions based on tax positions related to the current year		470			239			165
	Additions for tax positions of prior years		39			114			53
	Reductions for tax positions of prior years		(287	)		(413	)		(502	)
	Settlements		—			(36	)		(203	)
	Balance at end of year	$	1,171		$	949		$	1,045
	The Company accounts for interest and penalties related to uncertain tax positions as part of its provision for federal and state income taxes. The Company recognized net expense (credit) of $40,000, $(421,000) and $(43,000) in interest and penalties for the years ended December 31, 2014, 2013 and 2012, respectively. The Company had $306,000, $266,000 and $790,000 of accrued liabilities for the payment of interest and penalties at December 31, 2014, 2013 and 2012, respectively.

Leases

Leases	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Leases	(7) Leases
	The Company and its subsidiaries currently lease various facilities and equipment under a number of cancelable and noncancelable operating leases. Lease agreements for barges have terms from one to 12 years expiring at various dates through 2020. Lease agreements for towing vessels chartered by the Company have terms from 30 days to five years expiring at various dates through 2018; however, approximately half of the towing vessel charter agreements are for terms of one year or less. Total rental expense for the years ended December 31, 2014, 2013 and 2012 was as follows (in thousands):
		2014		2013		2012
	Rental expense:
	Marine equipment — barges	$	19,780	$	20,841	$	23,835
	Marine equipment — towing vessels		136,331		124,877		97,428
	Other buildings and equipment		9,146		10,298		9,952
	Rental expense	$	165,257	$	156,016	$	131,215
	Future minimum lease payments under operating leases that have initial or remaining noncancelable lease terms in excess of one year at December 31, 2014 were as follows (in thousands):
		Land, Buildings		Marine Equipment
		And Equipment		Barges		Towing Vessels		Total
	2015	$	7,716	$	13,930	$	89,491	$	111,137
	2016		6,351		8,872		35,656		50,879
	2017		5,761		7,473		17,746		30,980
	2018		5,104		6,594		4,212		15,910
	2019		3,523		3,567		—		7,090
	Thereafter		15,358		2,239		—		17,597
		$	43,813	$	42,675	$	147,105	$	233,593

Stock_Award_Plans

Stock Award Plans	12 Months Ended
	Dec. 31, 2014
Stock Award Plans [Abstract]
Stock Award Plans	(8) Stock Award Plans
	The Company has share-based compensation plans which are described below. The compensation cost that has been charged against earnings for the Company’s stock award plans and the income tax benefit recognized in the statement of earnings for stock awards for the years ended December 31, 2014, 2013 and 2012 were as follows (in thousands):
		2014			2013			2012
	Compensation cost	$	11,591		$	11,621		$	9,796
	Income tax benefit	$	4,358		$	4,370		$	3,644
	The Company has an employee stock award plan for selected officers and other key employees which provides for the issuance of stock options and restricted stock. The exercise price for each option equals the fair market value per share of the Company’s common stock on the date of grant. The terms of the options are seven years and vest ratably over three years. No performance awards payable in stock have been awarded under the plan. At December 31, 2014, 2,540,946 shares were available for future grants under the employee plan and no outstanding stock options under the employee plan were issued with stock appreciation rights.
	The following is a summary of the stock option activity under the employee plan described above for the years ended December 31, 2014, 2013 and 2012:
		Outstanding Non- Qualified or Nonincentive Stock Awards			Weighted Average Exercise Price
	Outstanding at December 31, 2011		445,674		$	36.81
	Granted		99,906		$	65.8
	Exercised		(191,955	)	$	35.65
	Canceled or expired		(2,452	)	$	58.28
	Outstanding at December 31, 2012		351,173		$	45.54
	Granted		111,527		$	70.94
	Exercised		(83,096	)	$	34.51
	Canceled or expired		—		$	—
	Outstanding at December 31, 2013		379,604		$	55.42
	Granted		75,204		$	98.91
	Exercised		(119,276	)	$	42.07
	Canceled or expired		(12,576	)	$	68.89
	Outstanding at December 31, 2014		322,956		$	69.95
	Under the employee plan, stock options exercisable were 157,140, 175,170 and 149,544 at December 31, 2014, 2013 and 2012, respectively.
	The following table summarizes information about the Company’s outstanding and exercisable stock options under the employee plan at December 31, 2014:
		Options Outstanding											Options Exercisable
	Range of Exercise Prices	Number Outstanding			Weighted Average Remaining Contractual Life in Years			Weighted Average Exercise Price			Aggregated Intrinsic Value		Number Exercisable		Weighted Average Exercise Price		Aggregated Intrinsic Value
	$31.35 – $36.35		16,910			2.1		$	32.82					16,910	$	32.82
	$46.74		56,629			3.1		$	46.74					56,629	$	46.74
	$65.28 – $70.65		172,246			4.6		$	68.39					82,946	$	67.56
	$86.96 – $96.85		37,730			6.1		$	93.89					655	$	86.96
	$101.46 – $114.11		39,441			6.2		$	103.12				─		$	─
	$31.35 – $114.11		322,956			4.6		$	69.95		$	4,863,000		157,140	$	56.4	$	3,829,000
	The following is a summary of the restricted stock award activity under the employee plan described above for the years ended December 31, 2014, 2013 and 2012:
		Unvested Restricted Stock Award Shares			Weighted Average Grant Date Fair Value Per Share
	Nonvested balance at December 31, 2011		475,632		$	36.43
	Granted		121,953		$	67.79
	Vested		(168,166	)	$	35.43
	Forfeited		(11,291	)	$	58.64
	Nonvested balance at December 31, 2012		418,128		$	45.39
	Granted		139,971		$	69.85
	Vested		(149,162	)	$	44.3
	Forfeited		(9,659	)	$	61.2
	Nonvested balance at December 31, 2013		399,278		$	54.92
	Granted		97,706		$	97.46
	Vested		(141,870	)	$	45.64
	Forfeited		(33,661	)	$	63.56
	Nonvested balance at December 31, 2014		321,453		$	71.04
	The Company has a director stock award plan for nonemployee directors of the Company which provides for the issuance of stock options and restricted stock. The director plan provides for the automatic grants of stock options and restricted stock to nonemployee directors on the date of first election as a director and after each annual meeting of stockholders. In addition, the director plan allows for the issuance of stock options or restricted stock in lieu of cash for all or part of the annual director fee at the option of the director. The exercise prices for all options granted under the plan are equal to the fair market value per share of the Company’s common stock on the date of grant. The terms of the options are ten years. The options granted to a director when first elected vest immediately. The options granted and restricted stock issued after each annual meeting of stockholders vest six months after the date of grant. Options granted and restricted stock issued in lieu of cash director fees vest in equal quarterly increments during the year to which they relate. At December 31, 2014, 559,881 shares were available for future grants under the director plan. The director stock award plan is intended as an incentive to attract and retain qualified independent directors.
	The following is a summary of the stock option activity under the director plan described above for the years ended December 31, 2014, 2013, and 2012:
		Outstanding Non- Qualified or Nonincentive Stock Awards			Weighted Average Exercise Price
	Outstanding at December 31, 2011		353,625		$	39.05
	Granted		66,306		$	62.39
	Exercised		(73,993	)	$	28.22
	Outstanding at December 31, 2012		345,938		$	45.84
	Granted		54,958		$	75.17
	Exercised		(80,574	)	$	46.75
	Outstanding at December 31, 2013		320,322		$	50.64
	Granted		42,000		$	99.52
	Exercised		(63,988	)	$	39.08
	Outstanding at December 31, 2014		298,334		$	60.01
	Under the director plan, options exercisable were 298,334, 320,082 and 345,360 at December 31, 2014, 2013 and 2012, respectively.
	The following table summarizes information about the Company’s outstanding and exercisable stock options under the director plan at December 31, 2014:
		Options Outstanding											Options Exercisable
	Range of Exercise Prices	Number Outstanding			Weighted Average Remaining Contractual Life in Years			Weighted Average Exercise Price			Aggregate Intrinsic Value		Number Exercisable		Weighted Average Exercise Price		Aggregate Intrinsic Value
	$20.28 – $29.60		30,000			1.9		$	25.87					30,000	$	25.87
$35.17 – $36.82		32,048			1.3		$	36.09					32,048	$	36.09
$41.24 – $56.45		91,022			4.2		$	51.87					91,022	$	51.87
$61.89 – $62.48		54,306			5.8		$	62.37					54,306	$	62.37
$75.17 – $99.52		90,958			7.2		$	86.41					90,958	$	86.41
$20.28 – $99.52		298,334			4.9		$	60.01		$	6,975,000		298,334	$	60.01	$	6,975,000
The following is a summary of the restricted stock award activity under the director plan described above for the years ended December 31, 2014, 2013 and 2012:
	Unvested Restricted Stock Award Shares			Weighted Average Grant Date Fair Value Per Share
Nonvested balance at December 31, 2011		1,748		$	58.07
Granted		10,383		$	62.99
Vested		(11,783	)	$	62.26
Nonvested balance at December 31, 2012		348		$	62.99
Granted		10,536		$	75.65
Vested		(10,500	)	$	75.23
Nonvested balance at December 31, 2013		384		$	75.65
Granted		8,160		$	99.52
Vested		(8,252	)	$	98.41
Nonvested balance at December 31, 2014		292		$	99.52
The total intrinsic value of all stock options exercised under all of the Company’s plans was $11,671,000, $6,703,000 and $6,768,000 for the years ended December 31, 2014, 2013 and 2012, respectively. The actual tax benefit realized for tax deductions from stock option exercises was $4,388,000, $2,520,000 and $2,518,000 for the years ended December 31, 2014, 2013 and 2012, respectively.
The total intrinsic value of all the restricted stock vestings under all of the Company’s plans was $14,847,000, $10,993,000 and $11,878,000 for the years ended December 31, 2014, 2013 and 2012, respectively. The actual tax benefit realized for tax deductions from restricted stock vestings was $5,583,000, $4,133,000 and $4,418,000 for the years ended December 31, 2014, 2013 and 2012, respectively.
As of December 31, 2014, there was $2,701,000 of unrecognized compensation cost related to nonvested stock options and $16,271,000 related to restricted stock. The stock options are expected to be recognized over a weighted average period of approximately 1.2 years and restricted stock over approximately 2.6 years. The total fair value of stock options vested was $3,759,000, $3,341,000 and $2,846,000 during the years ended December 31, 2014, 2013 and 2012, respectively. The fair value of the restricted stock vested was $14,847,000, $10,993,000 and $11,878,000 for the years ended December 31, 2014, 2013 and 2012, respectively.
The weighted average per share fair value of stock options granted during the years ended December 31, 2014, 2013 and 2012 was $36.05, $25.14 and $22.21, respectively. The fair value of the stock options granted during the years ended December 31, 2014, 2013 and 2012 was $4,226,000, $4,184,000 and $3,691,000, respectively. The Company currently uses treasury stock shares for restricted stock grants and stock option exercises. The fair value of each stock option was determined using the Black-Scholes option pricing model. The key input variables used in valuing the stock options during the years ended December 31, 2014, 2013 and 2012 were as follows:
	2014			2013			2012
Dividend yield	None			None			None
Average risk-free interest rate		2	%		1.1	%		1.1	%
Stock price volatility		33	%		34	%		33	%
Estimated option term	Six years or seven years			Six years or seven years			Six years or seven years

Retirement_Plans

Retirement Plans	12 Months Ended
	Dec. 31, 2014
Retirement Plans [Abstract]
Retirement Plans	(9) Retirement Plans
	The Company sponsors a defined benefit plan for its inland vessel personnel and shore based tankermen. The plan benefits are based on an employee’s years of service and compensation. The plan assets consist primarily of equity and fixed income securities.
	The fair value of plan assets was $242,275,000 and $254,523,000 at December 31, 2014 and 2013 respectively. As of December 31, 2014 and 2013, these assets were allocated among asset categories as follows:
	Asset Category		2014				2013				Current Minimum, Target and Maximum Allocation Policy
	U.S. equity securities			52	%			51	%			30% — 50%— 70	%
	International equity securities			18	%			21	%			0% — 20%— 30	%
	Debt securities			30	%			28	%			15% — 30%— 55	%
	Cash and cash equivalents			—	%			—	%			0% — 0%— 5	%
				100	%			100	%
	The plan assets are invested entirely in common collective trusts. These instruments are public investment vehicles valued using the net asset value provided by the administrator of the fund. The net asset value is classified within Level 2 of the valuation hierarchy as set forth in the accounting guidance for fair value measurements because the net asset value price is quoted on an inactive private market although the underlying investments are traded on an active market.
	The Company’s investment strategy focuses on total return on invested assets (capital appreciation plus dividend and interest income). The primary objective in the investment management of assets is to achieve long-term growth of principal while avoiding excessive risk. Risk is managed through diversification of investments within and among asset classes, as well as by choosing securities that have an established trading and underlying operating history.
	The Company makes various assumptions when determining defined benefit plan costs including, but not limited to, the current discount rate and the expected long-term return on plan assets. Discount rates are determined annually and are based on a yield curve that consists of a hypothetical portfolio of high quality corporate bonds with maturities matching the projected benefit cash flows. The Company assumed that plan assets would generate a long-term rate of return of 7.5% in 2014 and 2013. The Company developed its expected long-term rate of return assumption by evaluating input from investment consultants comparing historical returns for various asset classes with its actual and targeted plan investments. The Company believes that its long-term asset allocation, on average, will approximate the targeted allocation.
	The Company’s pension plan funding strategy has historically been to contribute an amount equal to the greater of the minimum required contribution under ERISA or the amount necessary to fully fund the plan on an accumulated benefit obligation (“ABO”) basis at the end of the fiscal year. The ABO is based on a variety of demographic and economic assumptions, and the pension plan assets’ returns are subject to various risks, including market and interest rate risk, making an accurate prediction of the pension plan contribution difficult. The Company’s pension plan funding was 100% of the pension plan’s ABO at December 31, 2014.
	The Company sponsors an unfunded defined benefit health care plan that provides limited postretirement medical benefits to employees who met minimum age and service requirements, and to eligible dependents. The plan limits cost increases in the Company’s contribution to 4% per year. The plan is contributory, with retiree contributions adjusted annually. The plan eliminated coverage for future retirees as of December 31, 2011. The Company also has an unfunded defined benefit supplemental executive retirement plan (“SERP”) that was assumed in an acquisition in 1999. That plan ceased to accrue additional benefits effective January 1, 2000.
	The following table presents the change in benefit obligation and plan assets for the Company’s defined benefit plans and postretirement benefit plan (in thousands):
																			Other Postretirement Benefits
			Pension Benefits																Postretirement
			Pension Plan								SERP								Welfare Plan
			2014				2013				2014				2013				2014				2013
	Change in benefit obligation
	Benefit obligation at beginning of year		$	249,960			$	266,911			$	1,529			$	1,746			$	2,307			$	2,854
	Service cost			10,645				12,824				—				—				—				—
	Interest cost			12,839				11,400				73				70				110				112
	Actuarial loss (gain)			66,640				(35,767	)			180				(138	)			(1,065	)			(600	)
	Gross benefits paid			(25,009	)			(5,408	)			(145	)			(149	)			(88	)			(59	)
	Benefit obligation at end of year		$	315,075			$	249,960			$	1,637			$	1,529			$	1,264			$	2,307
	Accumulated benefit obligation at end of year		$	241,592			$	200,577			$	1,637			$	1,529			$	—			$	—
	Weighted-average assumption used to determine benefit obligation at end of year
	Discount rate			4.1	%			5	%			4.1	%			5	%			4.1	%			5	%
	Rate of compensation increase			4.25	%			4.25	%			—				—				—				—
	Health care cost trend rate
	Initial rate			—				—				—				—				7	%			7	%
	Ultimate rate			—				—				—				—				5	%			5	%
	Years to ultimate			—				—				—				—				2019				2018
	Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation
	Increase		$	—			$	—			$	—			$	—			$	167			$	202
	Decrease			—				—				—				—				(141	)			(178	)
	Change in plan assets
	Fair value of plan assets at beginning of year		$	254,523			$	217,811			$	—			$	—			$	—			$	—
	Actual return on plan assets			12,761				42,120				—				—				—				—
	Employer contribution			—				—				145				149				88				59
	Gross benefits paid			(25,009	)			(5,408	)			(145	)			(149	)			(88	)			(59	)
	Fair value of plan assets at end of year		$	242,275			$	254,523			$	—			$	—			$	—			$	—
	The following table presents the funded status and amounts recognized in the Company’s consolidated balance sheet for the Company’s defined benefit plans and postretirement benefit plan at December 31, 2014 and 2013 (in thousands):
																			Other Postretirement Benefits
			Pension Benefits																Postretirement
			Pension Plan								SERP								Welfare Plan
			2014				2013				2014				2013				2014				2013
	Funded status at end of year
	Fair value of plan assets		$	242,275			$	254,523			$	—			$	—			$	—			$	—
	Benefit obligations			315,075				249,960				1,637				1,529				1,264				2,307
	Funded status and amount recognized at end of year recognized at end of year		$	(72,800	)		$	4,563			$	(1,637	)		$	(1,529	)		$	(1,264	)		$	(2,307	)
	Amounts recognized in the consolidated balance sheets
	Noncurrent asset		$	—			$	4,563			$	—			$	—			$	—			$	—
	Current liability			—				—				(141	)			(140	)			(83	)			(197	)
	Long-term liability			(72,800	)			—				(1,496	)			(1,389	)			(1,181	)			(2,110	)
	Amounts recognized in accumulated other comprehensive income
	Net actuarial loss (gain)		$	104,795			$	32,760			$	566			$	402			$	(6,787	)		$	(6,364	)
	Prior service cost (credit)			—				—				—				—				—				—
	Accumulated other compensation income		$	104,795			$	32,760			$	566			$	402			$	(6,787	)		$	(6,364	)
	The projected benefit obligation and fair value of plan assets for pension plans with a projected benefit obligation in excess of plan assets at December 31, 2014 and 2013 were as follows (in thousands):
			Pension Benefits
			Pension Plan								SERP
			2014				2013				2014				2013
Projected benefit obligation in excess of plan assets
Projected benefit obligation at end of year		$	315,075			$	—			$	1,637			$	1,529
Fair value of plan assets at end of year			242,275				—				—				—
The projected benefit obligation, accumulated benefit obligation and fair value of plan assets for pension plans with an accumulated benefit obligation in excess of plan assets at December 31, 2014 and 2013 were as follows (in thousands):
	Pension Benefits
	Pension Plan								SERP
	2014				2013				2014				2013
Accumulated benefit obligation in excess of plan assets
Projected benefit obligation at end of year		$	—			$	—			$	1,637			$	1,529
Accumulated benefit obligation at end of year			—				—				1,637				1,529
Fair value of plan assets at end of year			—				—				—				—
The following tables presents the expected cash flows for the Company’s defined benefit plans and postretirement benefit plan at December 31, 2014 and 2013 (in thousands):
																		Other Postretirement Benefits
		Pension Benefits																Postretirement
		Pension Plan								SERP								Welfare Plan
		2014				2013				2014				2013				2014				2013
Expected employer contributions
First year		$	8,400			$	—			$	143			$	144			$	84			$	202
																		Other Postretirement Benefits
		Pension Benefits																Postretirement
		Pension Plan								SERP								Welfare Plan
		2014				2013				2014				2013				2014				2013
Expected benefit payments (gross)
Year one		$	7,100			$	6,538			$	143			$	144			$	96			$	215
Year two			7,672				6,996				151				142				98				218
Year three			8,333				7,598				155				149				103				219
Year four			9,080				8,321				153				154				95				229
Year five			9,868				9,140				150				151				94				226
Next five years			62,666				59,242				621				663				445				976
																	Other Postretirement Benefits
	Pension Benefits																Postretirement
	Pension Plan								SERP								Welfare Plan
	2014				2013				2014				2013				2014				2013
Expected federal subsidy
Year one		$	—			$	—			$	—			$	—			$	(11	)		$	(13	)
Year two			—				—				—				—				(11	)			(13	)
Year three			—				—				—				—				(11	)			(13	)
Year four			—				—				—				—				(12	)			(12	)
Year five			—				—				—				—				(12	)			(12	)
Next five years			—				—				—				—				(55	)			(55	)
The components of net periodic benefit cost and other changes in plan assets and benefit obligations recognized in other comprehensive income for the Company’s defined benefit plans for the years ended December 31, 2014, 2013 and 2012 were as follows (in thousands):
		Pension Benefits
		Pension Plan												SERP
		2014				2013				2012				2014				2013				2012
Components of net periodic benefit cost
Service cost		$	10,645			$	12,824			$	10,206			$	—			$	—			$	—
Interest cost			12,839				11,400				10,506				73				70				73
Expected return on plan assets			(18,858	)			(16,127	)			(12,872	)			—				—				—
Amortization:
Actuarial loss			701				8,276				7,395				16				19				14
Prior service credit			—				—				—				—				—				—
Net periodic benefit cost			5,327				16,373				15,235				89				89				87
Other changes in plan assets and benefit obligations recognized in other comprehensive income
Current year actuarial loss (gain)			72,737				(61,759	)			23,557				180				(138	)			131
Recognition of actuarial loss			(701	)			(8,276	)			(7,395	)			(16	)			(19	)			(14	)
Recognition of prior service credit			—				—				—				—				—				—
Total recognized in other comprehensive income			72,036				(70,035	)			16,162				164				(157	)			117
Total recognized in net periodic benefit cost and other comprehensive income		$	77,363			$	(53,662	)		$	31,397			$	253			$	(68	)		$	204
Weighted average assumptions used to determine net periodic benefit cost
Discount rate			5	%			4.1	%			4.6	%			5	%			4.1	%			4.6	%
Expected long-term rate of return on plan assets			7.5	%			7.5	%			7.5	%			—				—				—
Rate of compensation increase			4.25	%			4.25	%			4.25	%			—				—				—
The estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost in 2015 are as follows (in thousands):
		Pension Benefits
		Pension Plan				SERP
Actuarial loss		$	7,845			$	28
Prior service credit			—				—
		$	7,845			$	28
The components of net periodic benefit cost and other changes in benefit obligations recognized in other comprehensive income for the Company’s postretirement benefit plan for the years ended December 31, 2014, 2013 and 2012 were as follows (in thousands):
		Other Postretirement Benefits
		Postretirement Welfare Plan
		2014				2013				2012
Components of net periodic benefit cost
Service cost		$	—			$	—			$	—
Interest cost			110				112				133
Amortization:
Actuarial gain			(649	)			(620	)			(618	)
Prior service cost			—				—				—
Net periodic benefit cost			(539	)			(508	)			(485	)
Other changes in benefit obligations recognized in other comprehensive income
Current year actuarial gain			(1,065	)			(600	)			(235	)
Recognition of actuarial gain			649				620				618
Recognition of prior service cost			—				—				—
Adjustment for actual Medicare Part D reimbursement			(8	)			(5	)			(10	)
Total recognized in other comprehensive income			(424	)			15				373
Total recognized in net periodic benefit cost and other comprehensive income		$	(963	)		$	(493	)		$	(112	)
Weighted average assumptions used to determine net periodic benefit cost
Discount rate			5	%			4.1	%			4.6	%
Health care cost trend rate:
Initial rate			7	%			7.5	%			7.5	%
Ultimate rate			5	%			5	%			5	%
Years to ultimate			2018				2018				2017
Effect of one-percentage-point change in assumed health care cost trend rate on aggregate service and interest cost
Increase		$	7			$	10			$	13
Decrease			(6	)			(9	)			(11	)
The estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost in 2015 are as follows (in thousands):
		Other Postretirement Benefits
		Postretirement Welfare Plan
Actuarial gain		$	(690	)
Prior service cost			—
		$	(690	)
The Company also contributes to a multiemployer pension plan pursuant to a collective bargaining agreement which covers certain vessel crew members of its coastal operations and expires on April 30, 2015. The Company began participation in the Seafarers Pension Trust (“SPT”) with the Penn acquisition on December 14, 2012.
Contributions to the SPT are made currently based on a per day worked basis and charged to expense as incurred and included in costs of sales and operating expenses in the consolidated statement of earnings. During 2014 and 2013, the Company made contributions of $1,290,000 and $1,368,000, respectively, to the SPT and none of the Company’s contributions to the SPT exceeded 5% of total contributions to the SPT nor did the Company pay any material surcharges.
The federal identification number of the SPT is 13-6100329 and the Certified Zone Status is Green at December 31, 2014. The Company’s future minimum contribution requirements under the SPT are unavailable because actuarial reports for the 2014 plan year are not yet complete and such contributions are subject to negotiations between the employers and the unions. The SPT was neither in endangered or critical status for the 2013 plan year, the latest period for which a report is available, as the funded status was in excess of 100%. Based on an actuarial valuation performed as of December 31, 2013, there would be no withdrawal liability if the Company chose to withdraw from the SPT although the Company currently has no intention of terminating its participation in the SPT.
In addition to the defined benefit plans, the Company sponsors various defined contribution plans for substantially all employees. The aggregate contributions to the plans were $23,356,000, $23,158,000 and $22,427,000 in 2014, 2013 and 2012, respectively.

Other_Comprehensive_Income

Other Comprehensive Income	12 Months Ended
	Dec. 31, 2014
Other Comprehensive Income [Abstract]
Other Comprehensive Income	(10) Other Comprehensive Income
	The Company’s changes in other comprehensive income for the years ended December 31, 2014, 2013 and 2012 were as follows (in thousands):
			2014									2013									2012
			Gross Amount			Income Tax (Provision) Benefit			Net Amount			Gross Amount			Income Tax (Provision) Benefit			Net Amount			Gross Amount			Income Tax (Provision) Benefit			Net Amount
	Pension and postretirement benefits (a):
	Amortization of net actuarial loss		$	68		$	(26	)	$	42		$	7,675		$	(2,942	)	$	4,733		$	6,791		$	(2,603	)	$	4,188
	Actuarial gains (losses)			(71,843	)		27,507			(44,336	)		62,503			(23,962	)		38,541			(23,443	)		8,985			(14,458	)
	Foreign currency translation adjustments			(35	)		—			(35	)		108			—			108			102			—			102
	Change in fair value of derivative instruments (b):
	Unrealized gains (losses)			24			(9	)		15			2,851			(996	)		1,855			16,364			(5,775	)		10,589
	Reclassified to net earnings			121			(51	)		70			(1,389	)		486			(903	)		(8,302	)		2,930			(5,372	)
	Total		$	(71,665	)	$	27,421		$	(44,244	)	$	71,748		$	(27,414	)	$	44,334		$	(8,488	)	$	3,537		$	(4,951	)
	(a)	Actuarial gains (losses) are amortized into costs of sales and operating expenses or selling, general and administrative expenses as appropriate. (See Note 9 – Retirement Plans)
	(b)	Reclassifications to net earnings of derivatives qualifying as effective hedges are recognized in interest expense or costs of sales and operating expenses as appropriate. (See Note 4 – Derivative Instruments)

Earnings_Per_Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Earnings Per Share	(11) Earnings Per Share
	The following table presents the components of basic and diluted earnings per share for the years ended December 31, 2014, 2013 and 2012 (in thousands, except per share amounts):
		2014			2013			2012
	Net earnings attributable to Kirby	$	282,006		$	253,061		$	209,438
	Undistributed earnings allocated to restricted shares		(1,643	)		(1,819	)		(1,618	)
	Income available to Kirby common stockholders — basic		280,363			251,242			207,820
	Undistributed earnings allocated to restricted shares		1,643			1,819			1,618
	Undistributed earnings reallocated to restricted shares		(1,637	)		(1,813	)		(1,612	)
	Income available to Kirby common stockholders — diluted	$	280,369		$	251,248		$	207,826
	Shares outstanding:
	Weighted average common stock issued and outstanding		57,006			56,762			55,897
	Weighted average unvested restricted stock		(332	)		(408	)		(431	)
	Weighted average common stock outstanding — basic		56,674			56,354			55,466
	Dilutive effect of stock options		193			198			208
	Weighted average common stock outstanding — diluted		56,867			56,552			55,674
	Net earnings per share attributable to Kirby common stockholders:
	Basic	$	4.95		$	4.46		$	3.75
	Diluted	$	4.93		$	4.44		$	3.73
	Certain outstanding options to purchase approximately 75,000, 2,000 and 100,000 shares of common stock were excluded in the computation of diluted earnings per share as of December 31, 2014, 2013 and 2012, respectively, as such stock options would have been antidilutive.

Quarterly_Results_Unaudited

Quarterly Results (Unaudited)	12 Months Ended
	Dec. 31, 2014
Quarterly Results (Unaudited) [Abstract]
Quarterly Results (Unaudited)	(12) Quarterly Results (Unaudited)
	The unaudited quarterly results for the year ended December 31, 2014 were as follows (in thousands, except per share amounts):
		Three Months Ended
		March 31,			June 30,			September 30,			December 31,
		2014			2014			2014			2014
	Revenues	$	589,246		$	628,054		$	680,721		$	668,297
	Costs and expenses		482,443			501,556			552,642			554,646
	Gain on disposition of assets		51			527			47			156
	Operating income		106,854			127,025			128,126			113,807
	Other income (expense)		(236	)		123			27			125
	Interest expense		(5,618	)		(5,469	)		(5,225	)		(5,149	)
	Earnings before taxes on income		101,000			121,679			122,928			108,783
	Provision for taxes on income		(37,989	)		(45,768	)		(45,715	)		(40,310	)
	Net earnings		63,011			75,911			77,213			68,473
	Less: Net earnings attributable to noncontrolling interests		(765	)		(919	)		(496	)		(422	)
	Net earnings attributable to Kirby	$	62,246		$	74,992		$	76,717		$	68,051
	Net earnings per share attributable to Kirby common stockholders:
	Basic	$	1.09		$	1.32		$	1.34		$	1.19
	Diluted	$	1.09		$	1.31		$	1.34		$	1.19
	The unaudited quarterly results for the year ended December 31, 2013 were as follows (in thousands, except per share amounts):
		Three Months Ended
		March 31,			June 30,			September 30,			December 31,
		2013			2013			2013			2013
	Revenues	$	558,785		$	563,908		$	551,105		$	568,397
	Costs and expenses		458,904			455,193			432,991			459,813
	Gain (loss) on disposition of assets		(32	)		537			223			160
	Operating income		99,849			109,252			118,337			108,744
	Other income		75			101			60			132
	Interest expense		(7,988	)		(7,219	)		(6,694	)		(5,971	)
	Earnings before taxes on income		91,936			102,134			111,703			102,905
	Provision for taxes on income		(34,384	)		(38,342	)		(42,007	)		(37,646	)
	Net earnings		57,552			63,792			69,696			65,259
	Less: Net earnings attributable to noncontrolling interests		(974	)		(699	)		(573	)		(992	)
	Net earnings attributable to Kirby	$	56,578		$	63,093		$	69,123		$	64,267
	Net earnings per share attributable to Kirby common stockholders:
	Basic	$	1		$	1.11		$	1.22		$	1.13
	Diluted	$	1		$	1.11		$	1.21		$	1.13
	Quarterly basic and diluted earnings per share may not total to the full year per share amounts, as the weighted average number of shares outstanding for each quarter fluctuates as a result of the assumed exercise of stock options.

Contingencies_and_Commitments

Contingencies and Commitments	12 Months Ended
	Dec. 31, 2014
Contingencies and Commitments [Abstract]
Contingencies and Commitments	(13) Contingencies and Commitments
	In June 2011, the Company as well as three other companies received correspondence from the United States Environmental Protection Agency (“EPA”) concerning ongoing cleanup and restoration activities under the Comprehensive Environmental Response, Compensation and Liability Act (“CERCLA”) with respect to a Superfund site, the Gulfco Marine Maintenance Site (“Gulfco”), located in Freeport, Texas. In prior years, various subsidiaries of the Company utilized a successor to Gulfco to perform tank barge cleaning services, sand blasting and repair on certain Company vessels. The EPA continues to investigate activities at the site to assess additional Potentially Responsible Parties (“PRPs”). Since 2005, four named PRPs have participated in the investigation, cleanup and restoration of the site under an administrative order from EPA. Information received to date indicates that approximately $4,500,000 has been incurred in connection with the cleanup effort in addition to EPA’s oversight costs of approximately $1,800,000. To date, neither the EPA nor the named PRPs have performed an allocation of potential liability in connection with the site. The named PRPs filed suit against the Company and approximately 21 other defendants seeking contribution and indemnity under CERCLA for costs incurred in connection with its activities in cleaning up the Gulfco Site. This matter is in initial stages of litigation.
	In 2009, the Company was named a PRP in addition to a group of approximately 250 named PRPs under CERCLA with respect to a Superfund site, the Portland Harbor Superfund site (“Portland Harbor”) in Portland, Oregon. The site was declared a Superfund site in December 2000 as a result of historical heavily industrialized use due to manufacturing, shipbuilding, petroleum storage and distribution, metals salvaging, and electrical power generation activities which led to contamination of Portland Harbor, an urban and industrial reach of the lower Willamette River located immediately downstream of downtown Portland. The Company’s involvement arises from four spills at the site after it was declared a Superfund site, as a result of predecessor entities’ actions in the area. To date, there is no information suggesting the extent of the costs or damages to be claimed from the 250 notified PRPs. Based on the nature of the involvement at the Portland Harbor site, the Company believes its potential contribution is de minimis; however, to date neither the EPA nor the named PRPs have performed an allocation of potential liability in connection with the site nor have they provided costs and expenses in connection with the site.
	In 2000, the Company and a group of approximately 45 other companies were notified that they are PRPs under CERCLA with respect to a Superfund site, the Palmer Barge Line Superfund Site (“Palmer”), located in Port Arthur, Texas. In prior years, Palmer had provided tank barge cleaning services to various subsidiaries of the Company. The Company and three other PRPs entered into an agreement with the EPA to perform a remedial investigation and feasibility study and, subsequently, a limited remediation was performed and is now complete. During the 2007 third quarter, five new PRPs entered into an agreement with the EPA related to the Palmer site. In July 2008, the EPA sent a letter to approximately 30 PRPs for the Palmer site, including the Company, indicating that it intends to pursue recovery of $2,949,000 of costs it incurred in relation to the site. The Company and the other PRPs submitted recommended pro rata allocations of costs among all PRPs to the EPA and the U.S. Department of Justice (“DOJ”) in order to resolve the EPA’s past costs claim which is under consideration by the DOJ.
	With respect to the above sites, the Company has recorded reserves, if applicable, for its estimated potential liability for its portion of the EPA’s past costs claim based on information developed to date including various factors such as the Company’s liability in proportion to other responsible parties and the extent to which such costs are recoverable from third parties.
	On July 25, 2011, a subsidiary of the Company was named as a defendant in the U.S. District Court for the Southern District of Texas - Galveston Division, in a complaint styled Figgs. v. Kirby Inland Marine, LP(“Kirby Inland Marine”), et al., which alleges that the plaintiff individually as a vessel tankerman, and on behalf of other current and former similarly situated vessel tankermen employed with the Company, is entitled to overtime pay under the Fair Labor Standards Act. Plaintiffs assert that vessel tankermen are not seamen who are expressly exempt from overtime pay provisions under the law. The case was conditionally certified as a collective action on December 22, 2011 at which time the Court prescribed a notice period for current and former employees to voluntarily participate as plaintiffs. The notice period closed on February 27, 2012. Plaintiffs seek compensatory damages in the form of back pay, attorneys’ fees, cost and liquidated damages. In a recent case that presented substantially the same facts and legal issues, the United States Court of Appeals for the Fifth Circuit ruled that vessel tankermen are seamen who are exempt from the overtime pay provisions of the Fair Labor Standards Act. While the Figgs case is still pending, the Company believes that, after the Fifth Circuit ruling, it will incur no material liability in the case.
	On March 22, 2014, a tank barge and towboat (the M/V Miss Susan), both owned by Kirby Inland Marine, a wholly owned subsidiary of the Company, were involved in a collision with the M/S Summer Wind on the Houston Ship Channel near Texas City, Texas. The tank barge was damaged in the collision resulting in a discharge of intermediate fuel oil from one of its cargo tanks. The USCG and the National Transportation Safety Board have named the Company and the Captain of the M/V Miss Susan, as well as the owner and the pilot of the M/S Summer Wind, as parties of interest in their investigation as to the cause of the incident. Sea Galaxy Ltd is the owner of the M/S Summer Wind. The Company is participating in the natural resource damage assessment and restoration process with federal and state government natural resource trustees.
	The Company and the owner of the M/S Summer Wind have filed actions in the U.S. District Court for the Southern District of Texas seeking exoneration from or limitation of liability relating to the foregoing incident as provided for in the federal rules of procedure for maritime claims. The two actions have been consolidated for procedural purposes since they both arise out of the same occurrence. There is a separate process for making a claim under the Oil Pollution Act of 1990 (“OPA”). The Company is processing claims properly presented, documented and recoverable under OPA. The Company is named as a party in other lawsuits filed in connection with this incident which are currently stayed by orders entered into by the court in the limitation proceedings, some of which may also have been presented as claims in the limitation proceeding. The actions include allegation of business interruption, loss of profit, loss of use of natural resources and seek unspecified economic and compensatory damages. In addition, the Company has received claims from numerous parties claiming property damage and various economic damages. The Company has also been named as a defendant in a civil action by two crewmembers of the M/V Miss Susan, alleging damages under the general maritime law and the Jones Act. The litigation and claims process is ongoing and many of the claims and lawsuits filed have not specified the amount of damages sought, but the Company believes it has adequate insurance coverage for pollution, marine and other potential liabilities arising from the incident. The Company believes it has accrued adequate reserves for the incident and does not expect the incident to have a material adverse effect on its business or financial condition.
	In addition, the Company is involved in various legal and other proceedings which are incidental to the conduct of its business, none of which in the opinion of management will have a material effect on the Company’s financial condition, results of operations or cash flows. Management believes that it has recorded adequate reserves and believes that it has adequate insurance coverage or has meritorious defenses for these other claims and contingencies.
	Certain Significant Risks and Uncertainties. The preparation of financial statements in conformity with United States generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. However, in the opinion of management, the amounts would be immaterial.
	The customer base of the marine transportation segment includes the major industrial petrochemical and chemical manufacturers, refining companies and agricultural chemical manufacturers operating in the United States. During 2014, approximately 80% of marine transportation’s inland revenues were from movements of such products under term contracts, typically ranging from one year to five years, with renewal options. During 2014, approximately 85% of the marine transportation’s coastal revenues were under term contracts. While the manufacturing and refining companies have generally been customers of the Company for numerous years (some as long as 40 years) and management anticipates a continuing relationship, there is no assurance that any individual contract will be renewed. No single customer of the marine transportation segment accounted for 10% of the Company’s revenues in 2014, 2013 and 2012.
	Major customers of the diesel engine services segment include inland and offshore barge operators, oilfield service companies, oil and gas operators and producers, compression companies, offshore fishing companies, marine and on-highway transportation companies, the USCG and United States Navy, and power generation, nuclear and industrial companies. The segment operates as an authorized distributor in 17 eastern states and the Caribbean, and as non-exclusive authorized service centers for Electro-Motive Diesel, Inc. (“EMD”) throughout the rest of the United States for marine and power generation applications. The diesel engine services segment’s relationship with EMD has been maintained for 49 years. The segment also operates factory-authorized full service marine dealerships for Cummins, Detroit Diesel and John Deere high-speed diesel engines and Allison transmissions and gears in the Gulf Coast region, as well as an authorized marine dealer for Caterpillar in Alabama, Kentucky, Louisiana and New Jersey.
	United has maintained continuous exclusive distribution rights for MTU and Allison since 1946. United is one of MTU’s top five distributors of MTU off-highway engines in North America with exclusive distribution rights in Oklahoma, Arkansas, Louisiana and Mississippi. In addition, as a distributor of Allison transmission products, United has distribution rights in Oklahoma, Arkansas and Louisiana. Finally, United is also the exclusive distributor for Daimler engines and related equipment in Oklahoma, Arkansas and Louisiana.
	The results of the diesel engine services segment are largely tied to the industries it serves and, therefore, can be influenced by the cycles of such industries. No single customer of the diesel engine services segment accounted for 10% of the Company’s revenues in 2014, 2013 and 2012.
	Weather can be a major factor in the day-to-day operations of the marine transportation segment. Adverse weather conditions, such as high or low water, tropical storms, hurricanes, tsunamis, fog and ice, can impair the operating efficiencies of the marine fleet. Shipments of products can be delayed or postponed by weather conditions, which are totally beyond the control of the Company. Adverse water conditions are also factors which impair the efficiency of the fleet and can result in delays, diversions and limitations on night passages, and dictate horsepower requirements and size of tows. Additionally, much of the inland waterway system is controlled by a series of locks and dams designed to provide flood control, maintain pool levels of water in certain areas of the country and facilitate navigation on the inland river system. Maintenance and operation of the navigable inland waterway infrastructure is a government function handled by the Army Corps of Engineers with costs shared by industry. Significant changes in governmental policies or appropriations with respect to maintenance and operation of the infrastructure could adversely affect the Company.
	The Company’s marine transportation segment is subject to regulation by the USCG, federal laws, state laws and certain international conventions, as well as numerous environmental regulations. The Company believes that additional safety, environmental and occupational health regulations may be imposed on the marine industry. There can be no assurance that any such new regulations or requirements, or any discharge of pollutants by the Company, will not have an adverse effect on the Company.
	The Company’s marine transportation segment competes principally in markets subject to the Jones Act, a federal cabotage law that restricts domestic marine transportation in the United States to vessels built and registered in the United States, and manned and owned by United States citizens. The Jones Act cabotage provisions occasionally come under attack by interests seeking to facilitate foreign flag competition in trades reserved for domestic companies and vessels under the Jones Act. The Company believes that continued efforts will be made to modify or eliminate the cabotage provisions of the Jones Act. If such efforts are successful, certain elements could have an adverse effect on the Company.
	The Company has issued guaranties or obtained standby letters of credit and performance bonds supporting performance by the Company and its subsidiaries of contractual or contingent legal obligations of the Company and its subsidiaries incurred in the ordinary course of business. The aggregate notional value of these instruments is $36,566,000 at December 31, 2014, including $7,433,000 in letters of credit and $29,133,000 in performance bonds. All of these instruments have an expiration date within four years. The Company does not believe demand for payment under these instruments is likely and expects no material cash outlays to occur in connection with these instruments.

Segment_Data

Segment Data	12 Months Ended
	Dec. 31, 2014
Segment Data [Abstract]
Segment Data	(14) Segment Data
	The Company’s operations are classified into two reportable business segments as follows:
	Marine Transportation — Marine transportation principally by United States flag vessels of liquid cargoes throughout the United States inland waterway system, along all three United States coasts, Alaska and Hawaii and, to a lesser extent, United States coastal transportation of dry-bulk cargoes. The principal products transported include petrochemicals, black oil, refined petroleum products and agricultural chemicals.
	Diesel Engine Services — Provides after-market services for medium-speed and high-speed diesel engines, reduction gears and ancillary products for marine and power generation applications, and distributes and services high-speed diesel engines, transmissions, pumps and compression products, and manufactures and remanufactures oilfield service equipment, including pressure pumping units, for the land-based pressure pumping and oilfield service markets.
	The Company’s two reportable business segments are managed separately based on fundamental differences in their operations. The Company’s accounting policies for the business segments are the same as those described in Note 1, Summary of Significant Accounting Policies. The Company evaluates the performance of its segments based on the contributions to operating income of the respective segments, and before income taxes, interest, gains or losses on disposition of assets, other nonoperating income, noncontrolling interests, accounting changes, and nonrecurring items. Intersegment sales for 2014, 2013 and 2012 were not significant.
	The following table sets forth by reportable segment the revenues, profit or loss, total assets, depreciation and amortization, and capital expenditures attributable to the principal activities of the Company for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		2014			2013			2012
	Revenues:
	Marine transportation	$	1,770,684		$	1,713,167		$	1,408,893
	Diesel engine services		795,634			529,028			703,765
		$	2,566,318		$	2,242,195		$	2,112,658
	Segment profit (loss):
	Marine transportation	$	429,864		$	408,255		$	311,755
	Diesel engine services		60,063			42,767			66,386
	Other		(35,537	)		(42,344	)		(37,615	)
		$	454,390		$	408,678		$	340,526
	Total assets:
	Marine transportation	$	3,317,696		$	3,046,692		$	2,951,723
	Diesel engine services		736,129			576,472			647,986
	Other		88,084			59,353			53,419
		$	4,141,909		$	3,682,517		$	3,653,128
	Depreciation and amortization:
	Marine transportation	$	154,019		$	149,574		$	129,857
	Diesel engine services		11,463			11,096			12,030
	Other		3,830			3,767			3,260
		$	169,312		$	164,437		$	145,147
	Capital expenditures:
	Marine transportation	$	340,315		$	237,964		$	274,351
	Diesel engine services		7,486			4,658			20,477
	Other		7,343			10,605			17,339
		$	355,144		$	253,227		$	312,167
	The following table presents the details of “Other” segment profit (loss) for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		2014			2013			2012
	General corporate expenses	$	(14,896	)	$	(15,728	)	$	(13,294	)
	Interest expense		(21,461	)		(27,872	)		(24,385	)
	Gain (loss) on disposition of assets		781			888			(14	)
	Other income		39			368			78
		$	(35,537	)	$	(42,344	)	$	(37,615	)
	The following table presents the details of “Other” total assets as of December 31, 2014, 2013 and 2012 (in thousands):
		2014			2013			2012
	General corporate assets	$	85,545		$	57,197		$	51,611
	Investment in affiliates		2,539			2,156			1,808
		$	88,084		$	59,353		$	53,419

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Related Party Transactions	(15) Related Party Transactions
	Richard J. Alario, a current director of the Company, is the Chairman of the Board, President and Chief Executive Officer of Key Energy Services, Inc. (“Key Energy”). Key Energy paid the Company $1,232,000 in 2014, $1,973,000 in 2013 and $13,152,000 in 2012 for oilfield service equipment and for parts and service. Such sales and service were in the ordinary course of business of the Company.
	The Company is a 50% owner of The Hollywood Camp, L.L.C. (“The Hollywood Camp”), a company that owns and operates a hunting and fishing facility used by the Company primarily for customer entertainment. The Hollywood Camp allocates lease and lodging expenses to its members based on their usage of the facilities. Key Energy paid The Hollywood Camp $1,634,000 in 2014, $1,112,000 in 2013 and $463,000 in 2012 for use of the facility.
	William M. Waterman, a current director of the Company, is the former President and owner (together with his family members) of Penn but resigned as an officer and director of Penn and affiliated companies contemporaneously with the closing of the acquisition of Penn by the Company on December 14, 2012. A portion of the purchase price consisting of approximately $24,000,000 in cash and 83,825 shares of Kirby stock was held in escrow to secure the sellers’ indemnification of the Company for breaches of representations and warranties in the purchase agreement. The escrow account terminated on March 31, 2014 and the cash and stock, net of a $17,000 claim, were distributed to Mr. Waterman, members of his family and a family trust.
	The husband of Amy D. Husted, Vice President — Legal of the Company, is a partner in the law firm of Strasburger & Price, LLP. The Company paid the law firm $1,184,000 in 2014, $851,000 in 2013 and $384,000 in 2012 for legal services in connection with matters in the ordinary course of business of the Company.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Summary of Significant Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation. The consolidated financial statements include the accounts of Kirby Corporation and all majority-owned subsidiaries (“the Company”). Two affiliated limited partnerships, in which the Company owns a 50% interest, is the general partner and has effective control and whose activities are an integral part of the operations of the Company, are consolidated. All other investments in which the Company owns 20% to 50% and exercises significant influence over operating and financial policies are accounted for using the equity method. All material intercompany accounts and transactions have been eliminated in consolidation. Certain reclassifications have been made to reflect the current presentation of financial information.
Cash Equivalents	Cash Equivalents. Cash equivalents consist of all short-term, highly liquid investments with maturities of three months or less at date of purchase.
Accounts Receivable	Accounts Receivable. In the normal course of business, the Company extends credit to its customers. The Company regularly reviews the accounts and makes adequate provisions for probable uncollectible balances. It is the Company’s opinion that the accounts have no impairment, other than that for which provisions have been made. Included in accounts receivable as of December 31, 2014 and 2013 were $143,615,000 and $69,481,000, respectively, of accruals for revenues earned which have not been invoiced as of the end of each year.
	The Company’s marine transportation and diesel engine services operations are subject to hazards associated with such businesses. The Company maintains insurance coverage against these hazards with insurance companies. Included in accounts receivable as of December 31, 2014 and 2013 were $92,379,000 and $22,396,000, respectively, of receivables from insurance companies to cover claims in excess of the Company’s deductible.
Concentrations Of Credit Risk	Concentrations of Credit Risk. Financial instruments which potentially subject the Company to concentrations of credit risk are primarily trade accounts receivables. The Company’s marine transportation customers include the major oil refining and petrochemical companies. The diesel engine services customers are oil and gas service companies, marine transportation companies, commercial fishing companies, power generation companies, and the United States government. The Company regularly reviews its accounts and estimates the amount of uncollectible receivables each period and establishes an allowance for uncollectible amounts. The amount of the allowance is based on the age of unpaid amounts, information about the current financial strength of customers, and other relevant information. Estimates of uncollectible amounts are revised each period, and changes are recorded in the period they become known.
Fair Value Of Financial Instruments	Fair Value of Financial Instruments. Cash, accounts receivable, accounts payable and accrued liabilities have carrying values that approximate fair value due to the short-term maturity of these financial instruments. The fair value of the Company’s debt instruments is more fully described in Note 5, Long-Term Debt.
Property, Maintenance And Repairs	Property, Maintenance and Repairs. Property is recorded at cost. Improvements and betterments are capitalized as incurred. Depreciation is recorded on the straight-line method over the estimated useful lives of the individual assets as follows: marine transportation equipment, 5-40 years; buildings, 10-40 years; other equipment, 2-10 years; and leasehold improvements, term of lease. When property items are retired, sold or otherwise disposed of, the related cost and accumulated depreciation are removed from the accounts with any gain or loss on the disposition included in the statement of earnings. Maintenance and repairs on vessels built for use on the inland waterways are charged to operating expense as incurred and includes the costs incurred in United States Coast Guard (“USCG”) inspections unless the shipyard extends the life or improves the operating capacity of the vessel which results in the costs being capitalized.
Drydocking on Ocean-Going Vessels	Drydocking on Ocean-Going Vessels. The Company’s ocean-going vessels are subject to regulatory drydocking requirements after certain periods of time to be inspected, have planned major maintenance performed and be recertified by the American Bureau of Shipping (“ABS”). These recertifications generally occur twice in a five year period. The Company defers the drydocking expenditures incurred on its ocean-going vessels due to regulatory marine inspections by the ABS and amortizes the costs of the shipyard over the period between drydockings, generally 30 or 60 months, depending on the type of major maintenance performed. Drydocking expenditures that extend the life or improve the operating capability of the vessel result in the costs being capitalized. The Company recognized amortization of capitalized planned major maintenance costs of $16,409,000, $9,029,000 and $3,924,000 for the years ended December 31, 2014, 2013 and 2012, respectively, in costs of sales and operating expenses. Routine repairs and maintenance on ocean-going vessels are expensed as incurred. Interest is capitalized on the construction of new ocean-going vessels. Interest expense excludes capitalized interest of $639,000 for the year ending December 31, 2014. No interest was capitalized for the years ending December 31, 2013 and 2012.
Environmental Liabilities	Environmental Liabilities. The Company expenses costs related to environmental events as they are incurred or when a loss is considered probable and estimable.
Goodwill	Goodwill. The excess of the purchase price over the fair value of identifiable net assets acquired in transactions accounted for as a purchase is included in goodwill. The Company conducted its annual goodwill impairment test at November 30, 2014 and 2013. For 2014 and 2013, the Company noted no impairment of goodwill. The Company will continue to conduct goodwill impairment tests as of November 30 of subsequent years, or whenever events or circumstances indicate that interim impairment testing is necessary. The gross carrying value of goodwill at December 31, 2014 and 2013 was $608,872,000 and accumulated amortization at December 31, 2014 and 2013 was $15,566,000. Accumulated impairment losses were $1,901,000 at December 31, 2014 and 2013.
	Net goodwill for the marine transportation segment was $381,243,000 at December 31, 2014 and 2013. Net goodwill for the diesel engine services segment was $210,162,000 at December 31, 2014 and 2013.
Revenue Recognition	Revenue Recognition. The majority of marine transportation revenue is derived from term contracts, ranging from one to five years, some of which have renewal options, and the remainder is from spot market movements. The majority of the term contracts are for terms of one year. The Company is a provider of marine transportation services for its customers and, in almost all cases, does not assume ownership of the products it transports. A term contract is an agreement with a specific customer to transport cargo from a designated origin to a designated destination at a set rate or at a daily rate. The rate may or may not escalate during the term of the contract, however, the base rate generally remains constant and contracts often include escalation provisions to recover changes in specific costs such as fuel. A spot contract is an agreement with a customer to move cargo from a specific origin to a designated destination for a rate negotiated at the time the cargo movement takes place. Spot contract rates are at the current “market” rate, including fuel, and are subject to market volatility. The Company uses a voyage accounting method of revenue recognition for its marine transportation revenues which allocates voyage revenue based on the percent of the voyage completed during the period. There is no difference in the recognition of revenue between a term contract and a spot contract.
	Diesel engine service products and services are generally sold based upon purchase orders or preferential service agreements with the customer that include fixed or determinable prices and that do not include right of return or significant post-delivery performance obligations. Diesel engine parts sales are recognized when title passes upon shipment to customers or when customer-specific acceptance requirements are met. Service revenue is recognized as the service is provided. Diesel manufacturing and assembly projects revenue is reported on the percentage of completion method of accounting using measurements of progress towards completion appropriate for the work performed.
Stock-Based Compensation	Stock-Based Compensation. The Company has share-based compensation plans covering selected officers and other key employees as well as the Company’s Board of Directors. Stock-based grants made under the Company’s stock plans are recorded at fair value on the date of the grant and the cost is recognized ratably over the vesting period of the stock option or restricted stock. Stock option grants are valued at the date of grant as calculated under the Black-Scholes option pricing model. The Company’s stock-based compensation plans are more fully described in Note 8, Stock Award Plans.
Taxes on Income	Taxes on Income. The Company follows the asset and liability method of accounting for income taxes. Under the asset and liability method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date.
Accrued Insurance	Accrued Insurance. Accrued insurance liabilities include estimates based on individual incurred claims outstanding and an estimated amount for losses incurred but not reported (“IBNR”) or fully developed based on past experience. Insurance premiums, IBNR losses and incurred claim losses, in excess of the Company’s deductible for 2014, 2013 and 2012 were $25,416,000, $22,971,000 and $17,876,000, respectively.
Noncontrolling Interests	Noncontrolling Interests. The Company has a majority interest in and is the general partner in several affiliated entities. In situations where losses applicable to the minority interest in the affiliated entities exceed the limited partners’ equity capital, such excess and any further loss attributable to the minority interest is charged against the Company’s interest in the affiliated entities. If future earnings materialize in the respective affiliated entities, the Company’s interest would be credited to the extent of any losses previously absorbed.
Treasury Stock	Treasury Stock. The Company follows the average cost method of accounting for treasury stock transactions.
Impairment of Long-Lived Assets and for Long-Lived Assets to be Disposed Of	Impairment of Long-Lived Assets and for Long-Lived Assets to Be Disposed Of. The Company reviews long-lived assets and certain identifiable intangibles for impairment by vessel class whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable.
	Recoverability on marine transportation assets is assessed based on vessel classes, not on individual assets, because identifiable cash flows for individual marine transportation assets are not available. Projecting customer contract volumes allows estimation of future cash flows by projecting pricing and utilization by vessel class but it is not practical to project which individual marine transportation asset will be utilized for any given contract. Because customers do not specify which particular vessel is used, prices are quoted based on vessel classes not individual assets. Nominations of vessels for specific jobs are determined on a day by day basis and are a function of the equipment class required and the geographic position of vessels within that class at that particular time as vessels within a class are interchangeable and provide the same service. The Company’s vessels are mobile assets and equipped to operate in geographic regions throughout the United States and the Company has in the past and expects to continue to move vessels from one region to another when it is necessary due to changing markets and it is economical to do so. Barge vessel classes are based on similar capacities, hull type, and type of product and towing vessels are based on similar hull type and horsepower. Recoverability of the vessel classes is measured by a comparison of the carrying amount of the assets to future net cash flows expected to be generated by the assets. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. Assets to be disposed of are reported at the lower of the carrying amount or fair value less costs to sell.

Inventories_Tables

Inventories (Tables)	12 Months Ended
	Dec. 31, 2014
Inventories [Abstract]
Schedule of Details of Inventories	The following table presents the details of inventories as of December 31, 2014 and 2013 (in thousands):
		December 31,		December 31,
		2014		2013
	Finished goods	$	179,760	$	120,751
	Work in process		12,594		15,136
		$	192,354	$	135,887

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Measurements [Abstract]
Schedule of Summarized Assets and Liabilities Measured at Fair Value on Recurring Basis	The following table summarizes the assets and liabilities measured at fair value on a recurring basis at December 31, 2013 (in thousands):
		Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Total Fair Value Measurements
		(Level 1)		(Level 2)		(Level 3)
	December 31, 2013:
	Assets:
	Derivatives	$	—	$	—	$	—	$	—
	Liabilities:
	Derivatives	$	—	$	59	$	—	$	59
	Contingent liabilities		—		—		4,903		4,903
		$	—	$	59	$	4,903	$	4,962

Derivative_Instruments_Tables

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2014
Derivative Instruments [Abstract]
Fair Value of Derivative Instruments Liabilities	The following table sets forth the fair value of the Company’s derivative instruments recorded as liabilities located on the consolidated balance sheet at December 31, 2014 and 2013 (in thousands):
	Liability Derivatives	Balance Sheet Location	2014		2013
	Derivatives designated as hedging instruments under ASC 815:
	Foreign currency contracts	Other accrued liabilities	$	—	$	59
	Foreign currency contracts	Other long-term liabilities		—		—
	Interest rate contracts	Other accrued liabilities		—		—
	Total derivatives designated as hedging instruments under ASC 815		$	—	$	59
	Total liability derivatives		$	—	$	59
Cash Flow Hedges	The following table sets forth the location and amount of gains and losses on the Company’s derivative instruments in the consolidated statements of earnings for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Location of Gain (Loss) Reclassified from Accumulated OCI into	Amount of Gain (Loss) Recognized in OCI on Derivatives
			(Effective Portion)
	Derivatives in ASC 815 Cash	Income
	Flow Hedging Relationships:	(Effective Portion)	2014		2013			2012
	Interest rate contracts	Interest expense	$	—	$	1,486		$	7,716
	Foreign exchange contracts	Cost of sales and operating expenses		145		(23	)		346
	Total		$	145	$	1,463		$	8,062
	Derivatives in ASC 815 Cash	Location of Gain (Loss) Reclassified from Accumulated OCI into Income	Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)
	Flow Hedging Relationships:	(Effective Portion)	2014		2013			2012
	Interest rate contracts	Interest expense	$	—	$	(1,389	)	$	(8,321	)
	Foreign exchange contracts	Cost of sales and operating expenses		121		—			19
	Total		$	121	$	(1,389	)	$	(8,302	)

LongTerm_Debt_Tables

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2014
Long-Term Debt [Abstract]
Schedule of Long-Term Debt	Long-term debt at December 31, 2014 and 2013 consisted of the following (in thousands):
		2014		2013
	Long-term debt, including current portion:
	$150,000,000 senior notes Series A due February 27, 2020	$	150,000	$	150,000
	$350,000,000 senior notes Series B due February 27, 2023		350,000		350,000
	$540,000,000 term loan due July 1, 2016		100,000		208,000
	$325,000,000 revolving credit facility due November 9, 2015		116,700		41,150
	$10,000,000 credit line due June 29, 2015		—		—
		$	716,700	$	749,150
Schedule of Aggregate Payments due on the Long-Term Debt	The aggregate payments due on the long-term debt in each of the next five years were as follows (in thousands):
	2015	$	116,700
	2016		100,000
	2017		—
	2018		—
	2019		—
	Thereafter		500,000
		$	716,700

Taxes_on_Income_Tables

Taxes on Income (Tables)	12 Months Ended
	Dec. 31, 2014
Taxes on Income [Abstract]
Earnings Before Taxes	Earnings before taxes on income and details of the provision for taxes on income for the years ended December 31, 2014, 2013 and 2012 were as follows (in thousands):
		2014			2013			2012
	Earnings before taxes on income — United States	$	454,390		$	408,678		$	340,526
	Provision for taxes on income:
	Federal:
	Current	$	81,953		$	41,008		$	41,297
	Deferred		72,920			97,586			71,767
	State and local		14,909			13,785			14,843
		$	169,782		$	152,379		$	127,907
Schedule of Effective Income Tax Rate Reconciliation	The Company’s provision for taxes on income varied from the statutory federal income tax rate for the years ended December 31, 2014, 2013 and 2012 due to the following:
		2014			2013			2012
	United States income tax statutory rate		35	%		35	%		35	%
	State and local taxes, net of federal benefit		2.2			2.2			2.8
	Other – net		0.2			0.1			(.2	)
			37.4	%		37.3	%		37.6	%
Schedule of Deferred Tax Assets and Liabilities	The tax effects of temporary differences that give rise to significant portions of the current deferred tax assets and non-current deferred tax assets and liabilities at December 31, 2014 and 2013 were as follows (in thousands):
		2014			2013
	Current deferred tax assets:
	Compensated absences	$	854		$	782
	Allowance for doubtful accounts		3,111			1,927
	Insurance accruals		2,858			2,572
	Other		3,739			4,177
		$	10,562		$	9,458
	Non-current deferred tax assets and liabilities:
	Deferred tax assets:
	Postretirement health care benefits	$	2,795		$	3,015
	Insurance accruals		3,325			2,781
	Deferred compensation		10,157			9,526
	Unrealized loss on derivative financial instruments		—			51
	Unrealized loss on defined benefit plans		34,501			9,379
	Operating loss carryforwards		515			5,699
	Other		20,687			17,925
			71,980			48,376
	Deferred tax liabilities:
	Property		(547,388	)		(487,187	)
	Deferred state taxes		(49,503	)		(46,798	)
	Pension benefits		(11,198	)		(13,063	)
	Goodwill and other intangibles		(37,936	)		(26,120	)
	Other		(21,724	)		(19,318	)
			(667,749	)		(592,486	)
		$	(595,769	)	$	(544,110	)
Reconciliation of Liability for Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of the liability for unrecognized tax benefits for the years ended December 31, 2014, 2013 and 2012, is as follows (in thousands):
		2014			2013			2012
	Balance at beginning of year	$	949		$	1,045		$	1,532
	Additions based on tax positions related to the current year		470			239			165
	Additions for tax positions of prior years		39			114			53
	Reductions for tax positions of prior years		(287	)		(413	)		(502	)
	Settlements		—			(36	)		(203	)
	Balance at end of year	$	1,171		$	949		$	1,045

Leases_Tables

Leases (Tables)	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Schedule of Rent Expense	Total rental expense for the years ended December 31, 2014, 2013 and 2012 was as follows (in thousands):
		2014		2013		2012
	Rental expense:
	Marine equipment — barges	$	19,780	$	20,841	$	23,835
	Marine equipment — towing vessels		136,331		124,877		97,428
	Other buildings and equipment		9,146		10,298		9,952
	Rental expense	$	165,257	$	156,016	$	131,215
Schedule of Future Minimum Lease Payments under Operating Leases	Future minimum lease payments under operating leases that have initial or remaining noncancelable lease terms in excess of one year at December 31, 2014 were as follows (in thousands):
		Land, Buildings		Marine Equipment
		And Equipment		Barges		Towing Vessels		Total
	2015	$	7,716	$	13,930	$	89,491	$	111,137
	2016		6,351		8,872		35,656		50,879
	2017		5,761		7,473		17,746		30,980
	2018		5,104		6,594		4,212		15,910
	2019		3,523		3,567		—		7,090
	Thereafter		15,358		2,239		—		17,597
		$	43,813	$	42,675	$	147,105	$	233,593

Stock_Award_Plans_Tables

Stock Award Plans (Tables)	12 Months Ended
	Dec. 31, 2014
Stock Award Plans [Abstract]
Compensation Cost Breakdown in Statement of Earnings	The Company has share-based compensation plans which are described below. The compensation cost that has been charged against earnings for the Company’s stock award plans and the income tax benefit recognized in the statement of earnings for stock awards for the years ended December 31, 2014, 2013 and 2012 were as follows (in thousands):
		2014			2013			2012
	Compensation cost	$	11,591		$	11,621		$	9,796
	Income tax benefit	$	4,358		$	4,370		$	3,644
Summary of Stock Option Activity under Employee Plans	The following is a summary of the stock option activity under the employee plan described above for the years ended December 31, 2014, 2013 and 2012:
		Outstanding Non- Qualified or Nonincentive Stock Awards			Weighted Average Exercise Price
	Outstanding at December 31, 2011		445,674		$	36.81
	Granted		99,906		$	65.8
	Exercised		(191,955	)	$	35.65
	Canceled or expired		(2,452	)	$	58.28
	Outstanding at December 31, 2012		351,173		$	45.54
	Granted		111,527		$	70.94
	Exercised		(83,096	)	$	34.51
	Canceled or expired		—		$	—
	Outstanding at December 31, 2013		379,604		$	55.42
	Granted		75,204		$	98.91
	Exercised		(119,276	)	$	42.07
	Canceled or expired		(12,576	)	$	68.89
	Outstanding at December 31, 2014		322,956		$	69.95
	The following table summarizes information about the Company’s outstanding and exercisable stock options under the employee plan at December 31, 2014:
		Options Outstanding											Options Exercisable
	Range of Exercise Prices	Number Outstanding			Weighted Average Remaining Contractual Life in Years			Weighted Average Exercise Price			Aggregated Intrinsic Value		Number Exercisable		Weighted Average Exercise Price		Aggregated Intrinsic Value
	$31.35 – $36.35		16,910			2.1		$	32.82					16,910	$	32.82
	$46.74		56,629			3.1		$	46.74					56,629	$	46.74
	$65.28 – $70.65		172,246			4.6		$	68.39					82,946	$	67.56
	$86.96 – $96.85		37,730			6.1		$	93.89					655	$	86.96
	$101.46 – $114.11		39,441			6.2		$	103.12				─		$	─
	$31.35 – $114.11		322,956			4.6		$	69.95		$	4,863,000		157,140	$	56.4	$	3,829,000
	The following is a summary of the stock option activity under the director plan described above for the years ended December 31, 2014, 2013, and 2012:
		Outstanding Non- Qualified or Nonincentive Stock Awards			Weighted Average Exercise Price
	Outstanding at December 31, 2011		353,625		$	39.05
	Granted		66,306		$	62.39
	Exercised		(73,993	)	$	28.22
	Outstanding at December 31, 2012		345,938		$	45.84
	Granted		54,958		$	75.17
	Exercised		(80,574	)	$	46.75
	Outstanding at December 31, 2013		320,322		$	50.64
	Granted		42,000		$	99.52
	Exercised		(63,988	)	$	39.08
	Outstanding at December 31, 2014		298,334		$	60.01
	The following table summarizes information about the Company’s outstanding and exercisable stock options under the director plan at December 31, 2014:
		Options Outstanding											Options Exercisable
	Range of Exercise Prices	Number Outstanding			Weighted Average Remaining Contractual Life in Years			Weighted Average Exercise Price			Aggregate Intrinsic Value		Number Exercisable		Weighted Average Exercise Price		Aggregate Intrinsic Value
	$20.28 – $29.60		30,000			1.9		$	25.87					30,000	$	25.87
	$35.17 – $36.82		32,048			1.3		$	36.09					32,048	$	36.09
	$41.24 – $56.45		91,022			4.2		$	51.87					91,022	$	51.87
	$61.89 – $62.48		54,306			5.8		$	62.37					54,306	$	62.37
	$75.17 – $99.52		90,958			7.2		$	86.41					90,958	$	86.41
	$20.28 – $99.52		298,334			4.9		$	60.01		$	6,975,000		298,334	$	60.01	$	6,975,000
Summary of Restricted Stock Award Activity	The following is a summary of the restricted stock award activity under the employee plan described above for the years ended December 31, 2014, 2013 and 2012:
		Unvested Restricted Stock Award Shares			Weighted Average Grant Date Fair Value Per Share
	Nonvested balance at December 31, 2011		475,632		$	36.43
	Granted		121,953		$	67.79
	Vested		(168,166	)	$	35.43
	Forfeited		(11,291	)	$	58.64
	Nonvested balance at December 31, 2012		418,128		$	45.39
	Granted		139,971		$	69.85
	Vested		(149,162	)	$	44.3
	Forfeited		(9,659	)	$	61.2
	Nonvested balance at December 31, 2013		399,278		$	54.92
	Granted		97,706		$	97.46
	Vested		(141,870	)	$	45.64
	Forfeited		(33,661	)	$	63.56
	Nonvested balance at December 31, 2014		321,453		$	71.04
	The following is a summary of the restricted stock award activity under the director plan described above for the years ended December 31, 2014, 2013 and 2012:
		Unvested Restricted Stock Award Shares			Weighted Average Grant Date Fair Value Per Share
	Nonvested balance at December 31, 2011		1,748		$	58.07
	Granted		10,383		$	62.99
	Vested		(11,783	)	$	62.26
	Nonvested balance at December 31, 2012		348		$	62.99
	Granted		10,536		$	75.65
	Vested		(10,500	)	$	75.23
	Nonvested balance at December 31, 2013		384		$	75.65
	Granted		8,160		$	99.52
	Vested		(8,252	)	$	98.41
	Nonvested balance at December 31, 2014		292		$	99.52
Summary of Stock Option Valuation Assumptions	The key input variables used in valuing the stock options during the years ended December 31, 2014, 2013 and 2012 were as follows:
		2014			2013			2012
	Dividend yield	None			None			None
	Average risk-free interest rate		2	%		1.1	%		1.1	%
	Stock price volatility		33	%		34	%		33	%
	Estimated option term	Six years or seven years			Six years or seven years			Six years or seven years

Retirement_Plans_Tables

Retirement Plans (Tables)	12 Months Ended
	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Summary of Asset Allocation	As of December 31, 2014 and 2013, these assets were allocated among asset categories as follows:
	Asset Category		2014				2013				Current Minimum, Target and Maximum Allocation Policy
	U.S. equity securities			52	%			51	%			30% — 50%— 70	%
	International equity securities			18	%			21	%			0% — 20%— 30	%
	Debt securities			30	%			28	%			15% — 30%— 55	%
	Cash and cash equivalents			—	%			—	%			0% — 0%— 5	%
				100	%			100	%
Schedule of Change in Benefit Obligation	The following table presents the change in benefit obligation and plan assets for the Company’s defined benefit plans and postretirement benefit plan (in thousands):
																			Other Postretirement Benefits
			Pension Benefits																Postretirement
			Pension Plan								SERP								Welfare Plan
			2014				2013				2014				2013				2014				2013
	Change in benefit obligation
	Benefit obligation at beginning of year		$	249,960			$	266,911			$	1,529			$	1,746			$	2,307			$	2,854
	Service cost			10,645				12,824				—				—				—				—
	Interest cost			12,839				11,400				73				70				110				112
	Actuarial loss (gain)			66,640				(35,767	)			180				(138	)			(1,065	)			(600	)
	Gross benefits paid			(25,009	)			(5,408	)			(145	)			(149	)			(88	)			(59	)
	Benefit obligation at end of year		$	315,075			$	249,960			$	1,637			$	1,529			$	1,264			$	2,307
	Accumulated benefit obligation at end of year		$	241,592			$	200,577			$	1,637			$	1,529			$	—			$	—
Weighted-Average Assumption Used to Determine Benefit Obligation and Net Periodic Benefit Cost	Weighted-average assumption used to determine benefit obligation at end of year
	Discount rate			4.1	%			5	%			4.1	%			5	%			4.1	%			5	%
	Rate of compensation increase			4.25	%			4.25	%			—				—				—				—
	Health care cost trend rate
	Initial rate			—				—				—				—				7	%			7	%
	Ultimate rate			—				—				—				—				5	%			5	%
	Years to ultimate			—				—				—				—				2019				2018
Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rate	Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation
	Increase		$	—			$	—			$	—			$	—			$	167			$	202
	Decrease			—				—				—				—				(141	)			(178	)
Summary of Change in Plan Assets	Change in plan assets
	Fair value of plan assets at beginning of year		$	254,523			$	217,811			$	—			$	—			$	—			$	—
	Actual return on plan assets			12,761				42,120				—				—				—				—
	Employer contribution			—				—				145				149				88				59
	Gross benefits paid			(25,009	)			(5,408	)			(145	)			(149	)			(88	)			(59	)
	Fair value of plan assets at end of year		$	242,275			$	254,523			$	—			$	—			$	—			$	—
Summary of Funded Status at End of Year	The following table presents the funded status and amounts recognized in the Company’s consolidated balance sheet for the Company’s defined benefit plans and postretirement benefit plan at December 31, 2014 and 2013 (in thousands):
																			Other Postretirement Benefits
			Pension Benefits																Postretirement
			Pension Plan								SERP								Welfare Plan
			2014				2013				2014				2013				2014				2013
	Funded status at end of year
	Fair value of plan assets		$	242,275			$	254,523			$	—			$	—			$	—			$	—
	Benefit obligations			315,075				249,960				1,637				1,529				1,264				2,307
	Funded status and amount recognized at end of year recognized at end of year		$	(72,800	)		$	4,563			$	(1,637	)		$	(1,529	)		$	(1,264	)		$	(2,307	)
Amounts Recognized in The Consolidated Balance Sheets	Amounts recognized in the consolidated balance sheets
	Noncurrent asset		$	—			$	4,563			$	—			$	—			$	—			$	—
	Current liability			—				—				(141	)			(140	)			(83	)			(197	)
	Long-term liability			(72,800	)			—				(1,496	)			(1,389	)			(1,181	)			(2,110	)
Amounts Recognized in Accumulated Other Comprehensive Income	Amounts recognized in accumulated other comprehensive income
	Net actuarial loss (gain)		$	104,795			$	32,760			$	566			$	402			$	(6,787	)		$	(6,364	)
	Prior service cost (credit)			—				—				—				—				—				—
	Accumulated other compensation income		$	104,795			$	32,760			$	566			$	402			$	(6,787	)		$	(6,364	)
Projected Benefit Obligation in Excess Of Plan Assets	The projected benefit obligation and fair value of plan assets for pension plans with a projected benefit obligation in excess of plan assets at December 31, 2014 and 2013 were as follows (in thousands):
			Pension Benefits
			Pension Plan								SERP
			2014				2013				2014				2013
	Projected benefit obligation in excess of plan assets
	Projected benefit obligation at end of year		$	315,075			$	—			$	1,637			$	1,529
	Fair value of plan assets at end of year			242,275				—				—				—
Accumulated Benefit Obligation in Excess Of Plan Assets	The projected benefit obligation, accumulated benefit obligation and fair value of plan assets for pension plans with an accumulated benefit obligation in excess of plan assets at December 31, 2014 and 2013 were as follows (in thousands):
		Pension Benefits
		Pension Plan								SERP
		2014				2013				2014				2013
	Accumulated benefit obligation in excess of plan assets
	Projected benefit obligation at end of year		$	—			$	—			$	1,637			$	1,529
	Accumulated benefit obligation at end of year			—				—				1,637				1,529
	Fair value of plan assets at end of year			—				—				—				—
Schedule of Employer Contribution	The following tables presents the expected cash flows for the Company’s defined benefit plans and postretirement benefit plan at December 31, 2014 and 2013 (in thousands):
																			Other Postretirement Benefits
			Pension Benefits																Postretirement
			Pension Plan								SERP								Welfare Plan
			2014				2013				2014				2013				2014				2013
	Expected employer contributions
	First year		$	8,400			$	—			$	143			$	144			$	84			$	202
Expected Benefit Payments																			Other Postretirement Benefits
			Pension Benefits																Postretirement
			Pension Plan								SERP								Welfare Plan
			2014				2013				2014				2013				2014				2013
	Expected benefit payments (gross)
	Year one		$	7,100			$	6,538			$	143			$	144			$	96			$	215
	Year two			7,672				6,996				151				142				98				218
	Year three			8,333				7,598				155				149				103				219
	Year four			9,080				8,321				153				154				95				229
	Year five			9,868				9,140				150				151				94				226
	Next five years			62,666				59,242				621				663				445				976
Summary of Expected Federal Subsidy																		Other Postretirement Benefits
		Pension Benefits																Postretirement
		Pension Plan								SERP								Welfare Plan
		2014				2013				2014				2013				2014				2013
	Expected federal subsidy
	Year one		$	—			$	—			$	—			$	—			$	(11	)		$	(13	)
	Year two			—				—				—				—				(11	)			(13	)
	Year three			—				—				—				—				(11	)			(13	)
	Year four			—				—				—				—				(12	)			(12	)
	Year five			—				—				—				—				(12	)			(12	)
	Next five years			—				—				—				—				(55	)			(55	)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-Average Assumption Used to Determine Benefit Obligation and Net Periodic Benefit Cost	Weighted average assumptions used to determine net periodic benefit cost
	Discount rate			5	%			4.1	%			4.6	%			5	%			4.1	%			4.6	%
	Expected long-term rate of return on plan assets			7.5	%			7.5	%			7.5	%			—				—				—
	Rate of compensation increase			4.25	%			4.25	%			4.25	%			—				—				—
Components of Net Periodic Benefit Cost			Pension Benefits
			Pension Plan												SERP
			2014				2013				2012				2014				2013				2012
	Components of net periodic benefit cost
	Service cost		$	10,645			$	12,824			$	10,206			$	—			$	—			$	—
	Interest cost			12,839				11,400				10,506				73				70				73
	Expected return on plan assets			(18,858	)			(16,127	)			(12,872	)			—				—				—
	Amortization:
	Actuarial loss			701				8,276				7,395				16				19				14
	Prior service credit			—				—				—				—				—				—
	Net periodic benefit cost			5,327				16,373				15,235				89				89				87
	Other changes in plan assets and benefit obligations recognized in other comprehensive income
	Current year actuarial loss (gain)			72,737				(61,759	)			23,557				180				(138	)			131
	Recognition of actuarial loss			(701	)			(8,276	)			(7,395	)			(16	)			(19	)			(14	)
	Recognition of prior service credit			—				—				—				—				—				—
	Total recognized in other comprehensive income			72,036				(70,035	)			16,162				164				(157	)			117
	Total recognized in net periodic benefit cost and other comprehensive income		$	77,363			$	(53,662	)		$	31,397			$	253			$	(68	)		$	204
Estimated Amounts that will be Amortized from Accumulated Other Comprehensive Income into Net Periodic Benefit Cost	The estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost in 2015 are as follows (in thousands):
			Pension Benefits
			Pension Plan				SERP
	Actuarial loss		$	7,845			$	28
	Prior service credit			—				—
			$	7,845			$	28
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-Average Assumption Used to Determine Benefit Obligation and Net Periodic Benefit Cost	Weighted average assumptions used to determine net periodic benefit cost
	Discount rate			5	%			4.1	%			4.6	%
	Health care cost trend rate:
	Initial rate			7	%			7.5	%			7.5	%
	Ultimate rate			5	%			5	%			5	%
	Years to ultimate			2018				2018				2017
Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rate	Effect of one-percentage-point change in assumed health care cost trend rate on aggregate service and interest cost
	Increase		$	7			$	10			$	13
	Decrease			(6	)			(9	)			(11	)
Components of Net Periodic Benefit Cost			Other Postretirement Benefits
			Postretirement Welfare Plan
			2014				2013				2012
	Components of net periodic benefit cost
	Service cost		$	—			$	—			$	—
	Interest cost			110				112				133
	Amortization:
	Actuarial gain			(649	)			(620	)			(618	)
	Prior service cost			—				—				—
	Net periodic benefit cost			(539	)			(508	)			(485	)
	Other changes in benefit obligations recognized in other comprehensive income
	Current year actuarial gain			(1,065	)			(600	)			(235	)
	Recognition of actuarial gain			649				620				618
	Recognition of prior service cost			—				—				—
	Adjustment for actual Medicare Part D reimbursement			(8	)			(5	)			(10	)
	Total recognized in other comprehensive income			(424	)			15				373
	Total recognized in net periodic benefit cost and other comprehensive income		$	(963	)		$	(493	)		$	(112	)
Estimated Amounts that will be Amortized from Accumulated Other Comprehensive Income into Net Periodic Benefit Cost	The estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost in 2015 are as follows (in thousands):
			Other Postretirement Benefits
			Postretirement Welfare Plan
	Actuarial gain		$	(690	)
	Prior service cost			—
			$	(690	)

Other_Comprehensive_Income_Tab

Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2014
Other Comprehensive Income [Abstract]
Schedule of Changes in Other Comprehensive Income	The Company’s changes in other comprehensive income for the years ended December 31, 2014, 2013 and 2012 were as follows (in thousands):
			2014									2013									2012
			Gross Amount			Income Tax (Provision) Benefit			Net Amount			Gross Amount			Income Tax (Provision) Benefit			Net Amount			Gross Amount			Income Tax (Provision) Benefit			Net Amount
	Pension and postretirement benefits (a):
	Amortization of net actuarial loss		$	68		$	(26	)	$	42		$	7,675		$	(2,942	)	$	4,733		$	6,791		$	(2,603	)	$	4,188
	Actuarial gains (losses)			(71,843	)		27,507			(44,336	)		62,503			(23,962	)		38,541			(23,443	)		8,985			(14,458	)
	Foreign currency translation adjustments			(35	)		—			(35	)		108			—			108			102			—			102
	Change in fair value of derivative instruments (b):
	Unrealized gains (losses)			24			(9	)		15			2,851			(996	)		1,855			16,364			(5,775	)		10,589
	Reclassified to net earnings			121			(51	)		70			(1,389	)		486			(903	)		(8,302	)		2,930			(5,372	)
	Total		$	(71,665	)	$	27,421		$	(44,244	)	$	71,748		$	(27,414	)	$	44,334		$	(8,488	)	$	3,537		$	(4,951	)
	(a)	Actuarial gains (losses) are amortized into costs of sales and operating expenses or selling, general and administrative expenses as appropriate. (See Note 9 – Retirement Plans)
	(b)	Reclassifications to net earnings of derivatives qualifying as effective hedges are recognized in interest expense or costs of sales and operating expenses as appropriate. (See Note 4 – Derivative Instruments)

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Earnings Per Share	The following table presents the components of basic and diluted earnings per share for the years ended December 31, 2014, 2013 and 2012 (in thousands, except per share amounts):
		2014			2013			2012
	Net earnings attributable to Kirby	$	282,006		$	253,061		$	209,438
	Undistributed earnings allocated to restricted shares		(1,643	)		(1,819	)		(1,618	)
	Income available to Kirby common stockholders — basic		280,363			251,242			207,820
	Undistributed earnings allocated to restricted shares		1,643			1,819			1,618
	Undistributed earnings reallocated to restricted shares		(1,637	)		(1,813	)		(1,612	)
	Income available to Kirby common stockholders — diluted	$	280,369		$	251,248		$	207,826
	Shares outstanding:
	Weighted average common stock issued and outstanding		57,006			56,762			55,897
	Weighted average unvested restricted stock		(332	)		(408	)		(431	)
	Weighted average common stock outstanding — basic		56,674			56,354			55,466
	Dilutive effect of stock options		193			198			208
	Weighted average common stock outstanding — diluted		56,867			56,552			55,674
	Net earnings per share attributable to Kirby common stockholders:
	Basic	$	4.95		$	4.46		$	3.75
	Diluted	$	4.93		$	4.44		$	3.73

Quarterly_Results_Unaudited_Ta

Quarterly Results (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Results (Unaudited) [Abstract]
Schedule of Quarterly Results	The unaudited quarterly results for the year ended December 31, 2014 were as follows (in thousands, except per share amounts):
		Three Months Ended
		March 31,			June 30,			September 30,			December 31,
		2014			2014			2014			2014
	Revenues	$	589,246		$	628,054		$	680,721		$	668,297
	Costs and expenses		482,443			501,556			552,642			554,646
	Gain on disposition of assets		51			527			47			156
	Operating income		106,854			127,025			128,126			113,807
	Other income (expense)		(236	)		123			27			125
	Interest expense		(5,618	)		(5,469	)		(5,225	)		(5,149	)
	Earnings before taxes on income		101,000			121,679			122,928			108,783
	Provision for taxes on income		(37,989	)		(45,768	)		(45,715	)		(40,310	)
	Net earnings		63,011			75,911			77,213			68,473
	Less: Net earnings attributable to noncontrolling interests		(765	)		(919	)		(496	)		(422	)
	Net earnings attributable to Kirby	$	62,246		$	74,992		$	76,717		$	68,051
	Net earnings per share attributable to Kirby common stockholders:
	Basic	$	1.09		$	1.32		$	1.34		$	1.19
	Diluted	$	1.09		$	1.31		$	1.34		$	1.19
	The unaudited quarterly results for the year ended December 31, 2013 were as follows (in thousands, except per share amounts):
		Three Months Ended
		March 31,			June 30,			September 30,			December 31,
		2013			2013			2013			2013
	Revenues	$	558,785		$	563,908		$	551,105		$	568,397
	Costs and expenses		458,904			455,193			432,991			459,813
	Gain (loss) on disposition of assets		(32	)		537			223			160
	Operating income		99,849			109,252			118,337			108,744
	Other income		75			101			60			132
	Interest expense		(7,988	)		(7,219	)		(6,694	)		(5,971	)
	Earnings before taxes on income		91,936			102,134			111,703			102,905
	Provision for taxes on income		(34,384	)		(38,342	)		(42,007	)		(37,646	)
	Net earnings		57,552			63,792			69,696			65,259
	Less: Net earnings attributable to noncontrolling interests		(974	)		(699	)		(573	)		(992	)
	Net earnings attributable to Kirby	$	56,578		$	63,093		$	69,123		$	64,267
	Net earnings per share attributable to Kirby common stockholders:
	Basic	$	1		$	1.11		$	1.22		$	1.13
	Diluted	$	1		$	1.11		$	1.21		$	1.13

Segment_Data_Tables

Segment Data (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Data [Abstract]
Schedule of Segment Reporting Information, by Segment	The following table sets forth by reportable segment the revenues, profit or loss, total assets, depreciation and amortization, and capital expenditures attributable to the principal activities of the Company for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		2014			2013			2012
	Revenues:
	Marine transportation	$	1,770,684		$	1,713,167		$	1,408,893
	Diesel engine services		795,634			529,028			703,765
		$	2,566,318		$	2,242,195		$	2,112,658
	Segment profit (loss):
	Marine transportation	$	429,864		$	408,255		$	311,755
	Diesel engine services		60,063			42,767			66,386
	Other		(35,537	)		(42,344	)		(37,615	)
		$	454,390		$	408,678		$	340,526
	Total assets:
	Marine transportation	$	3,317,696		$	3,046,692		$	2,951,723
	Diesel engine services		736,129			576,472			647,986
	Other		88,084			59,353			53,419
		$	4,141,909		$	3,682,517		$	3,653,128
	Depreciation and amortization:
	Marine transportation	$	154,019		$	149,574		$	129,857
	Diesel engine services		11,463			11,096			12,030
	Other		3,830			3,767			3,260
		$	169,312		$	164,437		$	145,147
	Capital expenditures:
	Marine transportation	$	340,315		$	237,964		$	274,351
	Diesel engine services		7,486			4,658			20,477
	Other		7,343			10,605			17,339
		$	355,144		$	253,227		$	312,167
Schedule of Other Segment Reporting Information	The following table presents the details of “Other” segment profit (loss) for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		2014			2013			2012
	General corporate expenses	$	(14,896	)	$	(15,728	)	$	(13,294	)
	Interest expense		(21,461	)		(27,872	)		(24,385	)
	Gain (loss) on disposition of assets		781			888			(14	)
	Other income		39			368			78
		$	(35,537	)	$	(42,344	)	$	(37,615	)
	The following table presents the details of “Other” total assets as of December 31, 2014, 2013 and 2012 (in thousands):
		2014			2013			2012
	General corporate assets	$	85,545		$	57,197		$	51,611
	Investment in affiliates		2,539			2,156			1,808
		$	88,084		$	59,353		$	53,419

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Significant Accounting Policies [Line Items]
Limited partnership ownership (in hundredths)	50.00%
Accruals for revenues earned included in accounts receivable	$143,615,000	$69,481,000
Period in which recertification of ocean going vessels occur twice	5 years
Receivables from insurance companies to cover claims in excess included in accounts receivable	92,379,000	22,396,000
Interest Expense Excludes Capitalized Interest	639,000
Interest amount capitalized		0	0
Impairment of goodwill	0	0
Gross carrying value of goodwill	608,872,000	608,872,000
Accumulated amortization	15,566,000	15,566,000
Accumulated impairment losses	1,901,000	1,901,000
Net goodwill	591,405,000	591,405,000
Amortization of scheduled major maintenance costs	16,409,000	9,029,000	3,924,000
Accrued insurance liabilities	25,416,000	22,971,000	17,876,000
Minimum [Member]
Significant Accounting Policies [Line Items]
Other investments ownership percentage (in hundredths)	20.00%
Period of amortization of shipyard costs	30 months
Maximum [Member]
Significant Accounting Policies [Line Items]
Other investments ownership percentage (in hundredths)	50.00%
Period of amortization of shipyard costs	60 months
Buildings [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Estimated useful lives of the individual assets	10 years
Buildings [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Estimated useful lives of the individual assets	40 years
Other Equipment [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Estimated useful lives of the individual assets	2 years
Other Equipment [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Estimated useful lives of the individual assets	10 years
Marine Transportation Equipment [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Estimated useful lives of the individual assets	5 years
Marine Transportation Equipment [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Estimated useful lives of the individual assets	40 years
Marine Transportation Segment [Member]
Significant Accounting Policies [Line Items]
Net goodwill	381,243,000	381,243,000
Range of term contracts	1 year
Marine Transportation Segment [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Range of term contracts	1 year
Marine Transportation Segment [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Range of term contracts	5 years
Diesel Engine Services Segment [Member]
Significant Accounting Policies [Line Items]
Net goodwill	$210,162,000	$210,162,000

Inventories_Details

Inventories (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Details of inventories [Abstract]
Finished goods	$179,760	$120,751
Work in process	12,594	15,136
Inventory, Net, Total	$192,354	$135,887

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	12 Months Ended			3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2014	Mar. 31, 2013	Nov. 01, 2012	Apr. 15, 2011
Business Acquisition [Line Items]
Payment of contingent liability	($4,756,000)	($5,000,000)	$0
Allied Transportation Company [Member]
Business Acquisition [Line Items]
Earnout Provision						10,000,000
Fair value contingent earnout liability	0					9,756,000
Increase (decrease) in fair value of earnout liability	97,000	136,000
Payment of contingent liability				5,000,000	5,000,000
United Holdings LLC [Member]
Business Acquisition [Line Items]
Earnout Provision							50,000,000
Fair value contingent earnout liability		18,300,000					16,300,000
Increase (decrease) in fair value of earnout liability	0	0
Recurring [Member]
Assets [Abstract]
Derivatives		0
Liabilities [Abstract]
Derivatives		59,000
Contingent liabilities		4,903,000
Liabilities fair value		4,962,000
Quoted Prices In Active Markets For Identical Assets (Level 1) | Recurring [Member]
Assets [Abstract]
Derivatives		0
Liabilities [Abstract]
Derivatives		0
Contingent liabilities		0
Liabilities fair value		0
Significant Other Observable Inputs (Level 2) | Recurring [Member]
Assets [Abstract]
Derivatives		0
Liabilities [Abstract]
Derivatives		59,000
Contingent liabilities		0
Liabilities fair value		59,000
Significant Unobservable Inputs (Level 3) | Recurring [Member]
Assets [Abstract]
Derivatives		0
Liabilities [Abstract]
Derivatives		0
Contingent liabilities		4,903,000
Liabilities fair value		$4,903,000

Derivative_Instruments_Fair_Va

Derivative Instruments (Fair Value of Derivative Instruments) (Details) (Designated as Hedging Instrument [Member], USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Mar. 31, 2014
Derivative Instruments in Hedges, at Fair Value [Abstract]
Total derivatives designated as hedging instruments under ASC 815	$0	$59,000
Total liability derivatives	0	59,000
Interest Rate Swap [Member]
Derivative instruments - risk management [Abstract]
Termination date	28-Feb-13
Notional amount	200,000,000
Interest Rate Contract [Member] | Other Accrued Liabilities [Member]
Derivative Instruments in Hedges, at Fair Value [Abstract]
Fair value, liability derivatives	0	0
Foreign Currency Contracts [Member] | Other Accrued Liabilities [Member]
Derivative Instruments in Hedges, at Fair Value [Abstract]
Fair value, liability derivatives	0	59,000
Foreign Currency Contracts [Member] | Other Long-Term Liabilities [Member]
Derivative Instruments in Hedges, at Fair Value [Abstract]
Fair value, liability derivatives	0	0
Forward Contracts [Member]
Derivative instruments - risk management [Abstract]
Notional amount			$469,000

Derivative_Instruments_Cash_Fl

Derivative Instruments (Cash Flow Hedges) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives (Effective Portion)	$145	$1,463	$8,062
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	121	-1,389	-8,302
Cash Flow Hedging [Member] | Foreign Exchange Contract [Member] | Cost and Sales of Operating Expenses [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives (Effective Portion)	145	-23	346
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	121	0	19
Cash Flow Hedging [Member] | Interest Rate Contract [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives (Effective Portion)	0	1,486	7,716
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	$0	($1,389)	($8,321)

LongTerm_Debt_Narrative_Detail

Long-Term Debt, Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Senior Notes	$500,000,000
Additional notes issued	0	225,000,000	275,000,000
Current portion of long-term debt	116,700,000	0
Total debt outstanding, Fair value	705,215,000	710,377,000
Commitment fee (in hundredths)	0.30%
Senior Notes Series A Due February 27, 2020 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage (in hundredths)	2.72%
Additional notes issued	67,500,000
Credit facility, amount outstanding	150,000,000	150,000,000
Senior debt retired	82,500,000
Senior Notes Series B Due February 27, 2023 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage (in hundredths)	3.29%
Additional notes issued	157,500,000
Credit facility, amount outstanding	350,000,000	350,000,000
Senior debt retired	192,500,000
Term Loan Due July 1, 2016 [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	100,000,000	208,000,000
Revolving Credit Facility Due November 9, 2015 [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	116,700,000	41,150,000
Term Loan [Member]
Debt Instrument [Line Items]
Maturity date	1-Jul-16
Average borrowing under revolving credit facility	152,892,000
Senior debt retired	100,000,000
Current portion of long-term debt	0
Term loan, duration	5 years
Weighted average interest rate (in hundredths)	1.70%
Term Loan [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Interest rate, variable rate basis	LIBOR
Basis spread on variable rate (in hundredths)	1.50%
Term Loan [Member] | Alternate Base Rate [Member]
Debt Instrument [Line Items]
Interest rate, variable rate basis	Alternate Base Rate
Basis spread on variable rate (in hundredths)	0.50%
Senior Notes [Member]
Debt Instrument [Line Items]
Senior debt retired			200,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maturity date	9-Nov-15
Average borrowing under revolving credit facility	28,591,000
Commitment amount	25,000,000
Credit facility, amount outstanding	4,939,000
Weighted average interest rate (in hundredths)	1.70%
Revolving Credit Facility [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Interest rate, variable rate basis	LIBOR
Basis spread on variable rate (in hundredths)	1.50%
Revolving Credit Facility [Member] | Alternate Base Rate [Member]
Debt Instrument [Line Items]
Interest rate, variable rate basis	Alternate Base Rate
Basis spread on variable rate (in hundredths)	0.50%
Line Of Credit [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	$1,194,000

LongTerm_Debt_Schedule_of_Long

Long-Term Debt (Schedule of Long-Term Debt) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Long-term Debt	$716,700,000	$749,150,000
Senior Notes Series A Due February Twenty Seven Two Thousand Twenty [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	150,000,000	150,000,000
Credit facility, expiration date	27-Feb-20
Long term debt, face amount	150,000,000
Senior Notes Series B Due February Twenty Seven Two Thousand Twenty Three [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	350,000,000	350,000,000
Credit facility, expiration date	27-Feb-23
Long term debt, face amount	350,000,000
Credit Line Due June Twenty Nine Two Thousand Fifteen [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	0	0
Credit facility, expiration date	29-Jun-15
Long term debt, face amount	10,000,000
Term Loan Due July 1, 2016 [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	100,000,000	208,000,000
Credit facility, expiration date	1-Jul-16
Long term debt, face amount	540,000,000
Revolving Credit Facility Due November 9, 2015 [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	116,700,000	41,150,000
Credit facility, expiration date	9-Nov-15
Long term debt, face amount	325,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	$4,939,000

LongTerm_Debt_Schedule_Of_Aggr

Long-Term Debt (Schedule Of Aggregate Payments Due On The Long-Term Debt) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Long-Term Debt [Abstract]
2015	$116,700
2016	100,000
2017	0
2018	0
2019	0
Thereafter	500,000
Long-term Debt	$716,700	$749,150

Taxes_on_Income_Narrative_Deta

Taxes on Income (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Taxes on Income [Abstract]
Tax benefit realized from equity compensation plans	$6,119,000	$3,001,000	$3,212,000
Operating loss carryforwards	515,000	5,699,000
Expiration dates, operating loss carryforwards	31-Dec-30
Unrecognized tax benefits including interest and penalties	1,477,000
Amount that would impact the effective tax rate, if recognized	998,000
Income tax penalties and interest recognized	40,000	-421,000	-43,000
Accrued liabilities for payment of interest and penalties	$306,000	$266,000	$790,000
Minimum [Member] | State and Local Jurisdiction [Member]
Income Tax Examination [Line Items]
Years open to audit under the statute of limitations	2008
Minimum [Member] | Internal Revenue Service (IRS) [Member]
Income Tax Examination [Line Items]
Years open to audit under the statute of limitations	2011
Maximum [Member] | State and Local Jurisdiction [Member]
Income Tax Examination [Line Items]
Years open to audit under the statute of limitations	2013
Maximum [Member] | Internal Revenue Service (IRS) [Member]
Income Tax Examination [Line Items]
Years open to audit under the statute of limitations	2013

Taxes_on_Income_Earnings_Befor

Taxes on Income (Earnings Before Taxes) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Taxes on Income [Abstract]
Earnings before taxes on income - United States	$108,783	$122,928	$121,679	$101,000	$102,905	$111,703	$102,134	$91,936	$454,390	$408,678	$340,526
Federal [Abstract]
Current									81,953	41,008	41,297
Deferred									72,920	97,586	71,767
State and local									14,909	13,785	14,843
Total provision for taxes on income	$40,310	$45,715	$45,768	$37,989	$37,646	$42,007	$38,342	$34,384	$169,782	$152,379	$127,907

Taxes_on_Income_Schedule_Of_Ef

Taxes on Income (Schedule Of Effective Income Tax Rate Reconciliation) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Company's provision for taxes on income varied from the statutory federal income tax rate [Abstract]
United States income tax statutory rate (in hundredths)	35.00%	35.00%	35.00%
State and local taxes, net of federal benefit (in hundredths)	2.20%	2.20%	2.80%
Other - net (in hundredths)	0.20%	0.10%	-0.20%
Effective income tax rate (in hundredths)	37.40%	37.30%	37.60%

Taxes_on_Income_Schedule_Of_De

Taxes on Income (Schedule Of Deferred Tax Assets And Liabilities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current deferred tax assets [Abstract]
Compensated absences	$854	$782
Allowance for doubtful accounts	3,111	1,927
Insurance accruals	2,858	2,572
Other	3,739	4,177
Current deferred tax assets, Total	10,562	9,458
Deferred tax assets [Abstract]
Postretirement health care benefits	2,795	3,015
Insurance accruals	3,325	2,781
Deferred compensation	10,157	9,526
Unrealized loss on derivative financial instruments	0	51
Unrealized loss on defined benefit plans	34,501	9,379
Operating loss carryforwards	515	5,699
Other	20,687	17,925
Deferred tax assets	71,980	48,376
Deferred tax liabilities [Abstract]
Property	-547,388	-487,187
Deferred state taxes	-49,503	-46,798
Pension benefits	-11,198	-13,063
Goodwill and other intangibles	-37,936	-26,120
Other	-21,724	-19,318
Deferred tax liabilities	-667,749	-592,486
Deferred tax assets (liabilities)	($595,769)	($544,110)

Taxes_on_Income_Reconciliation

Taxes on Income (Reconciliation Of Liability For Unrecognized Tax Benefits) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of the beginning and ending amount of the liability for unrecognized tax benefits [Roll Forward]
Balance at beginning of year	$949	$1,045	$1,532
Additions based on tax positions related to the current year	470	239	165
Additions for tax positions of prior years	39	114	53
Reductions for tax positions of prior years	-287	-413	-502
Settlements	0	-36	-203
Balance at end of year	$1,171	$949	$1,045

Leases_Narrative_Details

Leases (Narrative) (Details)	12 Months Ended
	Dec. 31, 2014
Minimum [Member] | Tank Barges [Member]
Operating Leased Assets [Line Items]
Lease agreements expiring terms	1 year
Minimum [Member] | Towing Vessels [Member]
Operating Leased Assets [Line Items]
Lease agreements expiring terms	30 days
Maximum [Member] | Tank Barges [Member]
Operating Leased Assets [Line Items]
Lease agreements expiring terms	12 years
Maximum [Member] | Towing Vessels [Member]
Operating Leased Assets [Line Items]
Lease agreements expiring terms	5 years

Leases_Schedule_Of_Rent_Expens

Leases (Schedule Of Rent Expense) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property Subject To Or Available for Operating Lease [Line Items]
Rental expense	$165,257	$156,016	$131,215
Other Buildings and Equipment [Member]
Property Subject To Or Available for Operating Lease [Line Items]
Rental expense	9,146	10,298	9,952
Tank Barges [Member] | Marine Equipment [Member]
Property Subject To Or Available for Operating Lease [Line Items]
Rental expense	19,780	20,841	23,835
Towing Vessels [Member] | Marine Equipment [Member]
Property Subject To Or Available for Operating Lease [Line Items]
Rental expense	$136,331	$124,877	$97,428

Leases_Schedule_Of_Future_Mini

Leases (Schedule Of Future Minimum Lease Payments Under Operating Leases) (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Operating Leased Assets [Line Items]
2015	$111,137
2016	50,879
2017	30,980
2018	15,910
2019	7,090
Thereafter	17,597
Future minimum lease payments under operating leases	233,593
Marine Equipment [Member] | Tank Barges [Member]
Operating Leased Assets [Line Items]
2015	13,930
2016	8,872
2017	7,473
2018	6,594
2019	3,567
Thereafter	2,239
Future minimum lease payments under operating leases	42,675
Marine Equipment [Member] | Towing Vessels [Member]
Operating Leased Assets [Line Items]
2015	89,491
2016	35,656
2017	17,746
2018	4,212
2019	0
Thereafter	0
Future minimum lease payments under operating leases	147,105
Land Buildings and Equipment [Member]
Operating Leased Assets [Line Items]
2015	7,716
2016	6,351
2017	5,761
2018	5,104
2019	3,523
Thereafter	15,358
Future minimum lease payments under operating leases	$43,813

Stock_Award_Plans_Details

Stock Award Plans (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock Award Plans [Abstract]
Compensation cost	$11,591,000	$11,621,000	$9,796,000
Income tax benefit	4,358,000	4,370,000	3,644,000
Stock Award Plan Information [Abstract]
Term of grant	7 years
Vesting period	3 years
Share-based Compensation Plans Combined Disclosure [Abstract]
Intrinsic value of stock options exercised	11,671,000	6,703,000	6,768,000
Tax benefit from stock options exercised	4,388,000	2,520,000	2,518,000
Intrinsic value of restricted stock vestings	14,847,000	10,993,000	11,878,000
Tax benefit from restricted stock vesting	5,583,000	4,133,000	4,418,000
Fair value of options vested	3,759,000	3,341,000	2,846,000
Fair value of restricted stock vested	14,847,000	10,993,000	11,878,000
Fair value of stock options granted (in dollars per share)	$36.05	$25.14	$22.21
Fair value of stock options granted	4,226,000	4,184,000	3,691,000
Employee Stock Award Plan [Member]
Stock Award Plan Information [Abstract]
Shares available for future grants (in shares)	2,540,946
Elected director first grant vesting period	The options granted when first elected a director vest immediately
Options Exercisable [Abstract]
Stock options exercisable	157,140	175,170	149,544
Unvested Restricted Stock Award Shares [Roll Forward]
Nonvested balance beginning of period, Unvested Restricted Stock Award Shares	399,278	418,128	475,632
Granted, Unvested Restricted Stock Award Shares (in shares)	97,706	139,971	121,953
Vested, Unvested Restricted Stock Award Shares (in shares)	-141,870	-149,162	-168,166
Forfeited, Unvested Restricted Stock Award Shares (in shares)	-33,661	-9,659	-11,291
Nonvested balance end of period, Unvested Restricted Stock Award Shares	321,453	399,278	418,128
Weighted Average Grant Date Fair Value Per Share [Abstract]
Nonvested balance beginning of period, Weighted Average Grant Date Fair Value Per Share	$54.92	$45.39	$36.43
Granted, Weighted Average Grant Date Fair Value Per Share (in dollars per share)	$97.46	$69.85	$67.79
Vested, Weighted Average Grant Date Fair Value Per Share (in dollars per share)	$45.64	$44.30	$35.43
Forfeited, Weighted Average Grant Date Fair Value Per Share (in dollars per share)	$63.56	$61.20	$58.64
Nonvested balance end of period, Weighted Average Grant Date Fair Value Per Share	$71.04	$54.92	$45.39
Employee Stock Award Plan [Member] | First Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	$36.35
Range of Exercise Prices, lower limit (in dollars per share)	$31.35
Options Outstanding [Abstract]
Number Outstanding (in shares)	16,910
Weighted Average Remaining Contractual Life (in years)	2 years 1 month 6 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$32.82
Options Exercisable [Abstract]
Number Exercisable (in shares)	16,910
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$32.82
Employee Stock Award Plan [Member] | Second Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	$46.74
Options Outstanding [Abstract]
Number Outstanding (in shares)	56,629
Weighted Average Remaining Contractual Life (in years)	3 years 1 month 6 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$46.74
Options Exercisable [Abstract]
Number Exercisable (in shares)	56,629
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$46.74
Employee Stock Award Plan [Member] | Third Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	$70.65
Range of Exercise Prices, lower limit (in dollars per share)	$65.28
Options Outstanding [Abstract]
Number Outstanding (in shares)	172,246
Weighted Average Remaining Contractual Life (in years)	4 years 7 months 6 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$68.39
Options Exercisable [Abstract]
Number Exercisable (in shares)	82,946
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$67.56
Employee Stock Award Plan [Member] | Fourth Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	$96.85
Range of Exercise Prices, lower limit (in dollars per share)	$86.96
Options Outstanding [Abstract]
Number Outstanding (in shares)	37,730
Weighted Average Remaining Contractual Life (in years)	6 years 1 month 6 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$93.89
Options Exercisable [Abstract]
Number Exercisable (in shares)	655
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$86.96
Employee Stock Award Plan [Member] | Fifth Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	$114.11
Range of Exercise Prices, lower limit (in dollars per share)	$101.46
Options Outstanding [Abstract]
Number Outstanding (in shares)	39,441
Weighted Average Remaining Contractual Life (in years)	6 years 2 months 12 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$103.12
Options Exercisable [Abstract]
Number Exercisable (in shares)	0
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$0
Employee Stock Award Plan [Member] | Full Exercise Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	$114.11
Range of Exercise Prices, lower limit (in dollars per share)	$31.35
Options Outstanding [Abstract]
Number Outstanding (in shares)	322,956
Weighted Average Remaining Contractual Life (in years)	4 years 7 months 6 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$69.95
Aggregate Intrinsic Value, Options Outstanding	4,863,000
Options Exercisable [Abstract]
Number Exercisable (in shares)	157,140
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$56.40
Aggregate Intrinsic Value, Options Exercisable	3,829,000
2000 Director Plan [Member]
Stock Award Plan Information [Abstract]
Term of grant	10 years
Vesting period	6 months
Shares available for future grants (in shares)	559,881
Options Exercisable [Abstract]
Stock options exercisable	298,334	320,082	345,360
Unvested Restricted Stock Award Shares [Roll Forward]
Nonvested balance beginning of period, Unvested Restricted Stock Award Shares	384	348	1,748
Granted, Unvested Restricted Stock Award Shares (in shares)	8,160	10,536	10,383
Vested, Unvested Restricted Stock Award Shares (in shares)	-8,252	-10,500	-11,783
Nonvested balance end of period, Unvested Restricted Stock Award Shares	292	384	348
Weighted Average Grant Date Fair Value Per Share [Abstract]
Nonvested balance beginning of period, Weighted Average Grant Date Fair Value Per Share	$75.65	$62.99	$58.07
Granted, Weighted Average Grant Date Fair Value Per Share (in dollars per share)	$99.52	$75.65	$62.99
Vested, Weighted Average Grant Date Fair Value Per Share (in dollars per share)	$98.41	$75.23	$62.26
Nonvested balance end of period, Weighted Average Grant Date Fair Value Per Share	$99.52	$75.65	$62.99
2000 Director Plan [Member] | First Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	$29.60
Range of Exercise Prices, lower limit (in dollars per share)	$20.28
Options Outstanding [Abstract]
Number Outstanding (in shares)	30,000
Weighted Average Remaining Contractual Life (in years)	1 year 10 months 24 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$25.87
Options Exercisable [Abstract]
Number Exercisable (in shares)	30,000
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$25.87
2000 Director Plan [Member] | Second Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	$36.82
Range of Exercise Prices, lower limit (in dollars per share)	$35.17
Options Outstanding [Abstract]
Number Outstanding (in shares)	32,048
Weighted Average Remaining Contractual Life (in years)	1 year 3 months 18 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$36.09
Options Exercisable [Abstract]
Number Exercisable (in shares)	32,048
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$36.09
2000 Director Plan [Member] | Third Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	$56.45
Range of Exercise Prices, lower limit (in dollars per share)	$41.24
Options Outstanding [Abstract]
Number Outstanding (in shares)	91,022
Weighted Average Remaining Contractual Life (in years)	4 years 2 months 12 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$51.87
Options Exercisable [Abstract]
Number Exercisable (in shares)	91,022
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$51.87
2000 Director Plan [Member] | Fourth Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	$62.48
Range of Exercise Prices, lower limit (in dollars per share)	$61.89
Options Outstanding [Abstract]
Number Outstanding (in shares)	54,306
Weighted Average Remaining Contractual Life (in years)	5 years 9 months 18 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$62.37
Options Exercisable [Abstract]
Number Exercisable (in shares)	54,306
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$62.37
2000 Director Plan [Member] | Fifth Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	$99.52
Range of Exercise Prices, lower limit (in dollars per share)	$75.17
Options Outstanding [Abstract]
Number Outstanding (in shares)	90,958
Weighted Average Remaining Contractual Life (in years)	7 years 2 months 12 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$86.41
Options Exercisable [Abstract]
Number Exercisable (in shares)	90,958
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$86.41
2000 Director Plan [Member] | Sixth Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	$99.52
Range of Exercise Prices, lower limit (in dollars per share)	$20.28
2000 Director Plan [Member] | Full Exercise Price Range [Member]
Options Outstanding [Abstract]
Number Outstanding (in shares)	298,334
Weighted Average Remaining Contractual Life (in years)	4 years 10 months 24 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$60.01
Aggregate Intrinsic Value, Options Outstanding	6,975,000
Options Exercisable [Abstract]
Number Exercisable (in shares)	298,334
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$60.01
Aggregate Intrinsic Value, Options Exercisable	6,975,000
Stock Options [Member]
Share-based Compensation Plans Combined Disclosure [Abstract]
Unrecognized compensation cost related to unvested awards	2,701,000
Weighted average period of recognition in years	1 year 2 months 12 days
Fair Value Assumptions [Abstract]
Dividend yield (in hundredths)	0.00%	0.00%	0.00%
Average risk-free interest rate (in hundredths)	2.00%	1.10%	1.10%
Stock price volatility (in hundredths)	33.00%	34.00%	33.00%
Stock Options [Member] | Minimum [Member]
Fair Value Assumptions [Abstract]
Estimated option term (in years)	6 years	6 years	6 years
Stock Options [Member] | Maximum [Member]
Fair Value Assumptions [Abstract]
Estimated option term (in years)	7 years	7 years	7 years
Stock Options [Member] | Employee Stock Award Plan [Member]
Outstanding Non-Qualified or Nonincentive Stock Awards [Roll Forward]
Outstanding at Period Start, Outstanding Non-Qualified or Nonincentive Stock Awards (in shares)	379,604	351,173	445,674
Granted, Outstanding Non-Qualified or Nonincentive Stock Awards (in shares)	75,204	111,527	99,906
Exercised, Outstanding Non-Qualified or Nonincentive Stock Awards (in shares)	-119,276	-83,096	-191,955
Canceled or expired, Outstanding Non-Qualified or Nonincentive Stock Awards (in shares)	-12,576	0	-2,452
Outstanding at Period End, Outstanding Non-Qualified or Nonincentive Stock Awards (in shares)	322,956	379,604	351,173
Weighted Average Exercise Price [Abstract]
Outstanding at Period Start, Weighted Average Exercise Price (in dollars per share)	$55.42	$45.54	$36.81
Granted, Weighted Average Exercise Price (in dollars per share)	$98.91	$70.94	$65.80
Exercised, Weighted Average Exercise Price (in dollars per share)	$42.07	$34.51	$35.65
Canceled or expired, Weighted Average Exercise Price (in dollars per share)	$68.89	$0	$58.28
Outstanding at Period End, Weighted Average Exercise Price (in dollars per share)	$69.95	$55.42	$45.54
Stock Options [Member] | 2000 Director Plan [Member]
Outstanding Non-Qualified or Nonincentive Stock Awards [Roll Forward]
Outstanding at Period Start, Outstanding Non-Qualified or Nonincentive Stock Awards (in shares)	320,322	345,938	353,625
Granted, Outstanding Non-Qualified or Nonincentive Stock Awards (in shares)	42,000	54,958	66,306
Exercised, Outstanding Non-Qualified or Nonincentive Stock Awards (in shares)	-63,988	-80,574	-73,993
Outstanding at Period End, Outstanding Non-Qualified or Nonincentive Stock Awards (in shares)	298,334	320,322	345,938
Weighted Average Exercise Price [Abstract]
Outstanding at Period Start, Weighted Average Exercise Price (in dollars per share)	$50.64	$45.84	$39.05
Granted, Weighted Average Exercise Price (in dollars per share)	$99.52	$75.17	$62.39
Exercised, Weighted Average Exercise Price (in dollars per share)	$39.08	$46.75	$28.22
Outstanding at Period End, Weighted Average Exercise Price (in dollars per share)	$60.01	$50.64	$45.84
Restricted Stock [Member]
Share-based Compensation Plans Combined Disclosure [Abstract]
Unrecognized compensation cost related to unvested awards	$16,271,000
Weighted average period of recognition in years	2 years 7 months 6 days

Retirement_Plans_Narrative_Det

Retirement Plans (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets (in hundredths)	7.50%	7.50%
Contribution percentage to defined contribution plan (in hundredths)	100.00%
Pension plan defined benefit plan cost increase limit percentage (in hundredths)	4.00%
Aggregate contributions to the plans	$23,356,000	$23,158,000	$22,427,000
Seafarers Pension Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension contributions	$1,290,000	$1,368,000
Contribution percentage to defined contribution plan (in hundredths)	100.00%
Maximum contribution limit (in hundredths)	5.00%

Retirement_Plans_Summary_Of_As

Retirement Plans (Summary Of Asset Allocation) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Asset allocations (in hundredths)	100.00%	100.00%
U.S. Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocations (in hundredths)	52.00%	51.00%
Target allocations, minimum (in hundredths)	30.00%
Target allocations (in hundredths)	50.00%
Target allocations, maximum (in hundredths)	70.00%
International Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocations (in hundredths)	18.00%	21.00%
Target allocations, minimum (in hundredths)	0.00%
Target allocations (in hundredths)	20.00%
Target allocations, maximum (in hundredths)	30.00%
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocations (in hundredths)	30.00%	28.00%
Target allocations, minimum (in hundredths)	15.00%
Target allocations (in hundredths)	30.00%
Target allocations, maximum (in hundredths)	55.00%
Cash And Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocations (in hundredths)	0.00%	0.00%
Target allocations, minimum (in hundredths)	0.00%
Target allocations (in hundredths)	0.00%
Target allocations, maximum (in hundredths)	5.00%

Retirement_Plans_Schedule_Of_C

Retirement Plans (Schedule Of Change In Benefit Obligation) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	$249,960	$266,911
Service cost	10,645	12,824	10,206
Interest cost	12,839	11,400	10,506
Actuarial loss (gain)	66,640	-35,767
Gross benefits paid	-25,009	-5,408
Benefit obligation at end of year	315,075	249,960	266,911
Accumulated benefit obligation at end of year	241,592	200,577
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	1,529	1,746
Service cost	0	0	0
Interest cost	73	70	73
Actuarial loss (gain)	180	-138
Gross benefits paid	-145	-149
Benefit obligation at end of year	1,637	1,529	1,746
Accumulated benefit obligation at end of year	1,637	1,529
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	2,307	2,854
Service cost	0	0	0
Interest cost	110	112	133
Actuarial loss (gain)	-1,065	-600
Gross benefits paid	-88	-59
Benefit obligation at end of year	1,264	2,307	2,854
Accumulated benefit obligation at end of year	$0	$0

Retirement_Plans_WeightedAvera

Retirement Plans (Weighted-Average Assumption Used To Determine Benefit Obligation) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate (in hundredths)	4.10%	5.00%
Rate of compensation increase (in hundredths)	4.25%	4.25%
Health care cost trend rate [Abstract]
Initial rate (in hundredths)	0.00%	0.00%
Ultimate rate (in hundredths)	0.00%	0.00%
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate (in hundredths)	4.10%	5.00%
Rate of compensation increase (in hundredths)	0.00%	0.00%
Health care cost trend rate [Abstract]
Initial rate (in hundredths)	0.00%	0.00%
Ultimate rate (in hundredths)	0.00%	0.00%
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate (in hundredths)	4.10%	5.00%
Rate of compensation increase (in hundredths)	0.00%	0.00%
Health care cost trend rate [Abstract]
Initial rate (in hundredths)	7.00%	7.00%
Ultimate rate (in hundredths)	5.00%	5.00%
Years to ultimate	2019	2018

Retirement_Plans_Effect_Of_One

Retirement Plans (Effect Of One-Percentage-Point Change In Assumed Health Care Cost Trend Rate) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation, Increase	$0	$0
Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation, Decrease	0	0
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation, Increase	0	0
Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation, Decrease	0	0
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation, Increase	167	202
Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation, Decrease	-141	-178
Effect of one-percentage-point change in assumed health care cost trend rate on aggregate service and interest cost, Increase	7	10	13
Effect of one-percentage-point change in assumed health care cost trend rate on aggregate service and interest cost, Decrease	($6)	($9)	($11)

Retirement_Plans_Summary_Of_Ch

Retirement Plans (Summary Of Change In Plan Assets) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	$254,523	$217,811
Actual return on plan assets	12,761	42,120
Employer contribution	0	0
Gross benefits paid	-25,009	-5,408
Fair value of plan assets at end of year	242,275	254,523
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contribution	145	149
Gross benefits paid	-145	-149
Fair value of plan assets at end of year	0	0
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contribution	88	59
Gross benefits paid	-88	-59
Fair value of plan assets at end of year	$0	$0

Retirement_Plans_Summary_Of_Fu

Retirement Plans (Summary Of Funded Status At End Of Year) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$242,275	$254,523	$217,811
Benefit obligations	315,075	249,960	266,911
Funded status and amount recognized at end of year	-72,800	4,563
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0	0
Benefit obligations	1,637	1,529	1,746
Funded status and amount recognized at end of year	-1,637	-1,529
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0	0
Benefit obligations	1,264	2,307	2,854
Funded status and amount recognized at end of year	($1,264)	($2,307)

Retirement_Plans_Amounts_Recog

Retirement Plans (Amounts Recognized In The Consolidated Balance Sheets) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Noncurrent asset	$0	$4,563
Current liability	0	0
Long-term liability	-72,800	0
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Noncurrent asset	0	0
Current liability	-141	-140
Long-term liability	-1,496	-1,389
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Noncurrent asset	0	0
Current liability	-83	-197
Long-term liability	($1,181)	($2,110)

Retirement_Plans_Amounts_Recog1

Retirement Plans (Amounts Recognized In Accumulated Other Comprehensive Income) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	$104,795	$32,760
Prior service cost (credit)	0	0
Accumulated other compensation income	104,795	32,760
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	566	402
Prior service cost (credit)	0	0
Accumulated other compensation income	566	402
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	-6,787	-6,364
Prior service cost (credit)	0	0
Accumulated other compensation income	($6,787)	($6,364)

Retirement_Plans_Projected_Ben

Retirement Plans (Projected Benefit Obligation In Excess Of Plan Assets) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	$315,075	$0
Fair value of plan assets at end of year	242,275	0
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	1,637	1,529
Fair value of plan assets at end of year	$0	$0

Retirement_Plans_Accumulated_B

Retirement Plans (Accumulated Benefit Obligation In Excess Of Plan Assets) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	$0	$0
Accumulated benefit obligation at end of year	0	0
Fair value of plan assets at end of year	0	0
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	1,637	1,529
Accumulated benefit obligation at end of year	1,637	1,529
Fair value of plan assets at end of year	$0	$0

Retirement_Plans_Schedule_Of_E

Retirement Plans (Schedule Of Employer Contribution) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions	$8,400	$0
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions	143	144
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions	$84	$202

Retirement_Plans_Expected_Bene

Retirement Plans (Expected Benefit Payments) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Year one	$7,100	$6,538
Year two	7,672	6,996
Year three	8,333	7,598
Year four	9,080	8,321
Year five	9,868	9,140
Next five years	62,666	59,242
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Year one	143	144
Year two	151	142
Year three	155	149
Year four	153	154
Year five	150	151
Next five years	621	663
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Year one	96	215
Year two	98	218
Year three	103	219
Year four	95	229
Year five	94	226
Next five years	$445	$976

Retirement_Plans_Summary_Of_Ex

Retirement Plans (Summary Of Expected Federal Subsidy) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Year one	$0	$0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	0
Next five years	0	0
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Year one	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	0
Next five years	0	0
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Year one	-11	-13
Year two	-11	-13
Year three	-11	-13
Year four	-12	-12
Year five	-12	-12
Next five years	($55)	($55)

Retirement_Plans_Components_Of

Retirement Plans (Components Of Net Periodic Benefit Cost) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Recognition of actuarial loss (gain)	$71,843	[1]	($62,503)	[1]	$23,443	[1]
Recognition of prior service credit (cost)	-68	[1]	-7,675	[1]	-6,791	[1]
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	10,645		12,824		10,206
Interest cost	12,839		11,400		10,506
Expected return on plan assets	-18,858		-16,127		-12,872
Actuarial loss (gain)	701		8,276		7,395
Prior service (credit) cost	0		0		0
Net periodic benefit cost	5,327		16,373		15,235
Current year actuarial loss (gain)	72,737		-61,759		23,557
Recognition of actuarial loss (gain)	-701		-8,276		-7,395
Recognition of prior service credit (cost)	0		0		0
Total recognized in other comprehensive income	72,036		-70,035		16,162
Total recognized in net periodic benefit cost and other comprehensive income	77,363		-53,662		31,397
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0		0		0
Interest cost	73		70		73
Expected return on plan assets	0		0		0
Actuarial loss (gain)	16		19		14
Prior service (credit) cost	0		0		0
Net periodic benefit cost	89		89		87
Current year actuarial loss (gain)	180		-138		131
Recognition of actuarial loss (gain)	-16		-19		-14
Recognition of prior service credit (cost)	0		0		0
Total recognized in other comprehensive income	164		-157		117
Total recognized in net periodic benefit cost and other comprehensive income	253		-68		204
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0		0		0
Interest cost	110		112		133
Actuarial loss (gain)	-649		-620		-618
Prior service (credit) cost	0		0		0
Net periodic benefit cost	-539		-508		-485
Current year actuarial loss (gain)	-1,065		-600		-235
Recognition of actuarial loss (gain)	649		620		618
Recognition of prior service credit (cost)	0		0		0
Adjustment for actual Medicare Part D reimbursement	-8		-5		-10
Total recognized in other comprehensive income	-424		15		373
Total recognized in net periodic benefit cost and other comprehensive income	($963)		($493)		($112)
[1]	(a) Actuarial gains (losses) are amortized into costs of sales and operating expenses or selling, general and administrative expenses as appropriate. (See Note 9 Retirement Plans)

Retirement_Plans_Weighted_Aver

Retirement Plans (Weighted Average Assumptions Used To Determine Net Periodic Benefit Cost) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets (in hundredths)	7.50%	7.50%
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate (in hundredths)	5.00%	4.10%	4.60%
Expected long-term rate of return on plan assets (in hundredths)	7.50%	7.50%	7.50%
Rate of compensation increase (in hundredths)	4.25%	4.25%	4.25%
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate (in hundredths)	5.00%	4.10%	4.60%
Expected long-term rate of return on plan assets (in hundredths)	0.00%	0.00%	0.00%
Rate of compensation increase (in hundredths)	0.00%	0.00%	0.00%
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate (in hundredths)	5.00%	4.10%	4.60%
Initial rate (in hundredths)	7.00%	7.50%	7.50%
Ultimate rate (in hundredths)	5.00%	5.00%	5.00%
Years to ultimate	2018	2018	2017

Retirement_Plans_Estimated_Amo

Retirement Plans (Estimated Amounts That Will Be Amortized From Accumulated Other Comprehensive Income Into Net Periodic Benefit Cost) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial gain (loss)	$7,845
Prior service cost (credit)	0
Estimated amounts to be amortized	7,845
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial gain (loss)	28
Prior service cost (credit)	0
Estimated amounts to be amortized	28
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial gain (loss)	-690
Prior service cost (credit)	0
Estimated amounts to be amortized	($690)

Other_Comprehensive_Income_Det

Other Comprehensive Income (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Pension and postretirement benefits [Abstract]
Amortization of net actuarial loss, Gross Amount	$68	[1]	$7,675	[1]	$6,791	[1]
Amortization of net actuarial loss, Income Tax (Provision) Benefit	-26	[1]	-2,942	[1]	-2,603	[1]
Amortization of net actuarial loss, Net Amount	42	[1]	4,733	[1]	4,188	[1]
Actuarial gains, Gross Amount	-71,843	[1]	62,503	[1]	-23,443	[1]
Actuarial gains, Income Tax (Provision) Benefit	27,507	[1]	-23,962	[1]	8,985	[1]
Actuarial gains, Net Amount	-44,336	[1]	38,541	[1]	-14,458	[1]
Foreign currency translation adjustments, Gross Amount	-35		108		102
Foreign currency translation adjustments, Income Tax (Provision) Benefit	0		0		0
Foreign currency translation adjustments, Net Amount	-35		108		102
Change in fair value of derivative instruments [Abstract]
Unrealized gains (losses), Gross Amount	24	[2]	2,851	[2]	16,364	[2]
Unrealized gains, Income Tax (Provision) Benefit	-9	[2]	-996	[2]	-5,775	[2]
Unrealized gains, Net Amount	15	[2]	1,855	[2]	10,589	[2]
Reclassified to net earnings, Gross Amount	121	[2]	-1,389	[2]	-8,302	[2]
Reclassified to net earnings, Income Tax (Provision) Benefit	-51	[2]	486	[2]	2,930	[2]
Reclassified to net earnings, Net Amount	70	[2]	-903	[2]	-5,372	[2]
Total other comprehensive income (loss), Gross Amount	-71,665	[2]	71,748	[2]	-8,488	[2]
Total other comprehensive income (loss), Income Tax (Provision) Benefit	27,421	[2]	-27,414	[2]	3,537	[2]
Total other comprehensive income (loss), net of taxes	($44,244)	[2]	$44,334	[2]	($4,951)	[2]
[1]	(a) Actuarial gains (losses) are amortized into costs of sales and operating expenses or selling, general and administrative expenses as appropriate. (See Note 9 Retirement Plans)
[2]	(b) Reclassifications to net earnings of derivatives qualifying as effective hedges are recognized in interest expense or costs of sales and operating expenses as appropriate. (See Note 4 Derivative Instruments)

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]
Net earnings attributable to Kirby	$68,051	$76,717	$74,992	$62,246	$64,267	$69,123	$63,093	$56,578	$282,006	$253,061	$209,438
Undistributed earnings allocated to restricted shares									-1,643	-1,819	-1,618
Income available to Kirby common stockholders - basic									280,363	251,242	207,820
Undistributed earnings allocated to restricted shares									1,643	1,819	1,618
Undistributed earnings reallocated to restricted shares									-1,637	-1,813	-1,612
Income available to Kirby common stockholders - diluted									$280,369	$251,248	$207,826
Weighted average common stock issued and outstanding (in shares)									57,006	56,762	55,897
Weighted average unvested restricted stock (in shares)									-332	-408	-431
Weighted average common stock outstanding - basic (in shares)									56,674	56,354	55,466
Dilutive effect of stock options (in shares)									193	198	208
Weighted average common stock outstanding - diluted (in shares)									56,867	56,552	55,674
Net earnings per share attributable to Kirby common stockholders [Abstract]
Basic (in dollars per share)	$1.19	$1.34	$1.32	$1.09	$1.13	$1.22	$1.11	$1	$4.95	$4.46	$3.75
Diluted (in dollars per share)	$1.19	$1.34	$1.31	$1.09	$1.13	$1.21	$1.11	$1	$4.93	$4.44	$3.73
Antidilutive Securities Excluded from Computation of Earnings Per Share (in shares)									75,000	2,000	100,000

Quarterly_Results_Schedule_Of_

Quarterly Results (Schedule Of Quarterly Results) (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Results (Unaudited) [Abstract]
Revenues	$668,297	$680,721	$628,054	$589,246	$568,397	$551,105	$563,908	$558,785	$2,566,318	$2,242,195	$2,112,658
Costs and expenses	554,646	552,642	501,556	482,443	459,813	432,991	455,193	458,904	2,090,506	1,806,013	1,747,825
Gain (loss) on disposition of assets	156	47	527	51	160	223	537	-32	781	888	-14
Operating income	113,807	128,126	127,025	106,854	108,744	118,337	109,252	99,849	475,812	436,182	364,833
Other income (expense)	125	27	123	-236	132	60	101	75	-345	20	-198
Interest expense	-5,149	-5,225	-5,469	-5,618	-5,971	-6,694	-7,219	-7,988	-21,461	-27,872	-24,385
Earnings before taxes on income	108,783	122,928	121,679	101,000	102,905	111,703	102,134	91,936	454,390	408,678	340,526
Provision for taxes on income	-40,310	-45,715	-45,768	-37,989	-37,646	-42,007	-38,342	-34,384	-169,782	-152,379	-127,907
Net earnings	68,473	77,213	75,911	63,011	65,259	69,696	63,792	57,552	284,608	256,299	212,619
Less: Net earnings attributable to noncontrolling interests	-422	-496	-919	-765	-992	-573	-699	-974	-2,602	-3,238	-3,181
Net earnings attributable to Kirby	$68,051	$76,717	$74,992	$62,246	$64,267	$69,123	$63,093	$56,578	$282,006	$253,061	$209,438
Net earnings per share attributable to Kirby common stockholders [Abstract]
Basic (in dollars per share)	$1.19	$1.34	$1.32	$1.09	$1.13	$1.22	$1.11	$1	$4.95	$4.46	$3.75
Diluted (in dollars per share)	$1.19	$1.34	$1.31	$1.09	$1.13	$1.21	$1.11	$1	$4.93	$4.44	$3.73

Contingencies_and_Commitments_

Contingencies and Commitments (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	Segment	Segment	Segment
Certain Significant Risks and Uncertainties [Abstract]
Customer relationship period	40 years
Number of single customers accounting more than 10% of segment revenue	0	0	0
Percentage of customers revenue (in hundredths)	10.00%	10.00%	10.00%
Segment operates authorized distributors	17
Diesel engine services segment's relationship	49 years
Guarantor Obligations [Line Items]
Issued guaranties	$36,566,000
Guarantor Obligations, Term	All of these instruments have an expiration date within four years.
Performance Bonds [Member]
Guarantor Obligations [Line Items]
Issued guaranties	29,133,000
Standby Letters of Credit [Member]
Guarantor Obligations [Line Items]
Issued guaranties	7,433,000
Gulfco Marine Superfund Site [Member]
Site Contingency [Line Items]
Number of other companies also named as Potentially Responsible Parties ("PRPs")	3
Number of companies named as Potentially Responsible Parties ("PRPs")	4
EPA incurred cleanup expense	4,500,000
EPA oversight costs	1,800,000
Number of defendants seeking contribution and indemnity under CERCLA	21
Portland Harbor Superfund Site [Member]
Site Contingency [Line Items]
Number of other companies also named as Potentially Responsible Parties ("PRPs")	250
Number of spills	4
Palmer Barge Line Superfund Site [Member]
Site Contingency [Line Items]
Number of other companies also named as Potentially Responsible Parties ("PRPs")	45
Number of other companies also in an investigation and feasibility study agreement with EPA	3
Number of new companies in an agreement with the EPA	5
Number of Potentially Responsible Parties notified by EPA of intent to recover costs	30
EPA notification intent to recover costs incurred	$2,949,000
Marine Transportation's [Member]
Certain Significant Risks and Uncertainties [Abstract]
Percentage of inland revenue (in hundredths)	80.00%
Percentage of costal revenue (in hundredths)	85.00%
Number of single customers accounting more than 10% of segment revenue	0	0	0
Marine Transportation's [Member] | Minimum [Member]
Certain Significant Risks and Uncertainties [Abstract]
Range of renewal options under term contracts	1 year
Marine Transportation's [Member] | Maximum [Member]
Certain Significant Risks and Uncertainties [Abstract]
Range of renewal options under term contracts	5 years

Segment_Data_Details

Segment Data (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
									Segment
Segment Data [Abstract]
Number of Reportable Segments									2
Revenues [Abstract]
Marine transportation									$1,770,684	$1,713,167	$1,408,893
Diesel engine services									795,634	529,028	703,765
Total revenues	668,297	680,721	628,054	589,246	568,397	551,105	563,908	558,785	2,566,318	2,242,195	2,112,658
Segment profit (loss)	108,783	122,928	121,679	101,000	102,905	111,703	102,134	91,936	454,390	408,678	340,526
Total assets	4,141,909				3,682,517				4,141,909	3,682,517	3,653,128
Depreciation and amortization									169,312	164,437	145,147
Capital expenditures									355,144	253,227	312,167
Other segment disclosures [Abstract]
Interest expense	-5,149	-5,225	-5,469	-5,618	-5,971	-6,694	-7,219	-7,988	-21,461	-27,872	-24,385
Gain (loss) on disposition of assets	-156	-47	-527	-51	-160	-223	-537	32	-781	-888	14
Other income (expense)	125	27	123	-236	132	60	101	75	-345	20	-198
Details of "Other" total assets [Abstract]
Investment in affiliates	2,539				2,156				2,539	2,156
Total assets	4,141,909				3,682,517				4,141,909	3,682,517	3,653,128
Reporting Segments [Member]
Revenues [Abstract]
Marine transportation									1,770,684	1,713,167	1,408,893
Diesel engine services									795,634	529,028	703,765
Total revenues									2,566,318	2,242,195	2,112,658
Segment profit (loss)									454,390	408,678	340,526
Depreciation and amortization									169,312	164,437	145,147
Capital expenditures									355,144	253,227	312,167
Marine Transportation [Member] | Reporting Segments [Member]
Revenues [Abstract]
Segment profit (loss)									429,864	408,255	311,755
Total assets	3,317,696				3,046,692				3,317,696	3,046,692	2,951,723
Depreciation and amortization									154,019	149,574	129,857
Capital expenditures									340,315	237,964	274,351
Details of "Other" total assets [Abstract]
Total assets	3,317,696				3,046,692				3,317,696	3,046,692	2,951,723
Diesel Engine Services [Member] | Reporting Segments [Member]
Revenues [Abstract]
Segment profit (loss)									60,063	42,767	66,386
Total assets	736,129				576,472				736,129	576,472	647,986
Depreciation and amortization									11,463	11,096	12,030
Capital expenditures									7,486	4,658	20,477
Details of "Other" total assets [Abstract]
Total assets	736,129				576,472				736,129	576,472	647,986
Other [Member]
Revenues [Abstract]
Total assets	88,084				59,353				88,084	59,353	53,419
Other segment disclosures [Abstract]
General corporate expenses									-14,896	-15,728	-13,294
Interest expense									-21,461	-27,872	-24,385
Gain (loss) on disposition of assets									781	888	-14
Other income (expense)									39	368	78
Profit (loss) from other segment									-35,537	-42,344	-37,615
Details of "Other" total assets [Abstract]
General corporate assets	85,545				57,197				85,545	57,197	51,611
Investment in affiliates	2,539				2,156				2,539	2,156	1,808
Total assets	88,084				59,353				88,084	59,353	53,419
Other [Member] | Reporting Segments [Member]
Revenues [Abstract]
Segment profit (loss)									-35,537	-42,344	-37,615
Total assets	88,084				59,353				88,084	59,353	53,419
Depreciation and amortization									3,830	3,767	3,260
Capital expenditures									7,343	10,605	17,339
Details of "Other" total assets [Abstract]
Total assets	$88,084				$59,353				$88,084	$59,353	$53,419

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	12 Months Ended
Share data in Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Hollywood Camp [Member]
Related Party Transaction [Line Items]
Ownership percentage (in hundredths)	50.00%
Facility expenses	$1,634,000	$1,112,000	$463,000
Amy D. Husted [Member]
Related Party Transaction [Line Items]
Legal services	1,184,000	851,000	384,000
William M. Waterman [Member]
Related Party Transaction [Line Items]
Cash portion of purchase price			24,000,000
Number of shares held in escrow (in shares)			83,825
Escrow Account Termination Date	31-Mar-14
Claim to escrow distribution	17,000
Richard J. Alario [Member]
Related Party Transaction [Line Items]
Oilfield service equipment	$1,232,000	$1,973,000	$13,152,000