Operating Expenses (Schedule of Acquisition Related Costs) (Details) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
May 31, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Share based payment expenses		$ 4,752		$ 4,752
Continuing employment costs		8,813	$ 8,880	14,289	$ 15,138
Other acquisition-related costs		22,948	603	31,575	1,800
Iron Planet Holdings Inc. [Member]
Share based payment expenses	$ 4,752	4,752		4,752
Legal costs		3,480		8,596
Other acquisition-related costs		13,955		16,530
Mascus International Holdings BV [Member]
Continuing employment costs		121	266	277	439
Other acquisition-related costs		23	32	23	750
Xcira LLC [Member]
Continuing employment costs		284	$ 305	666	$ 611
Petrowsky Auctioneers Inc. [Member]
Continuing employment costs		208		420
Other acquisition-related costs		4		4
Kramer Auctions Ltd. [Member]
Continuing employment costs		114		228
Other acquisition-related costs		$ 7		$ 79

Acquisition Related Share Based Compensation Expense

No definition available.

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- Definition

Costs incurred to effect a business combination which have been expensed during the period. Such costs could include business integration costs, systems integration and conversion costs, and severance and other employee-related costs.

+ References

No definition available.

+ Details

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- Definition

Payroll costs incurred (including equity-based compensation) that are directly related to services rendered by an entity during the reporting period.

+ 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 210.5-03.2(d))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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- Definition

The amount of expense provided in the period for legal costs incurred on or before the balance sheet date pertaining to resolved, pending or threatened litigation, including arbitration and mediation proceedings.

+ 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 210.5-03.3)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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