Business Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 item	Jun. 30, 2013
Business Segments
Number of reportable operating business segments			3
Revenue:
Total revenue	$ 11,342,475	$ 10,479,604	$ 21,893,371	$ 20,663,633
Gross profit:
Gross profit	191,516	188,458	379,548	370,837
Income from operations:
Income from operations	59,812	68,736	124,116	135,677
Aviation segment
Revenue:
Total revenue	4,436,505	3,745,070	8,686,308	7,675,658
Gross profit:
Gross profit	81,824	76,041	150,745	153,025
Marine segment
Revenue:
Total revenue	3,532,817	3,967,109	7,013,034	7,684,248
Gross profit:
Gross profit	48,841	52,332	96,683	94,014
Land segment
Revenue:
Total revenue	3,373,153	2,767,425	6,194,029	5,303,727
Gross profit:
Gross profit	60,851	60,085	132,120	123,798
Operating Segments
Income from operations:
Income from operations	72,479	79,057	150,105	156,576
Operating Segments \| Aviation segment
Income from operations:
Income from operations	37,152	33,873	67,223	68,753
Operating Segments \| Marine segment
Income from operations:
Income from operations	20,945	24,062	41,970	39,321
Operating Segments \| Land segment
Income from operations:
Income from operations	14,382	21,122	40,912	48,502
Corporate
Income from operations:
Income from operations	$ 12,667	$ 10,321	$ 25,989	$ 20,899

Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

Name:	us-gaap_GrossProfit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_GrossProfitAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The net result for the period of deducting operating expenses from operating revenues.

+ References

No definition available.

+ Details

Name:	us-gaap_OperatingIncomeLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_OperatingIncomeLossAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

+ Details

Name:	us-gaap_Revenues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_RevenuesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_SegmentReportingAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration