Segmented Information (Schedule Of Revenue And (Loss) Income Before Taxes by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting [Line Items]
Revenues	$ 135,462	$ 109,318	$ 155,477	$ 115,618	$ 138,457	$ 102,217	$ 141,835	$ 98,588	$ 515,875	$ 481,097	$ 467,403
Direct expenses, excluding depreciation and amortization									(56,026)	(57,884)	(54,008)
Selling, general and administrative expenses									(254,990)	(248,220)	(243,736)
Depreciation and amortization expenses									(42,032)	(44,536)	(43,280)
Impairment loss										(8,084)
Gain on disposition of property, plant and equipment									9,691	3,512	10,552
Foreign exchange gain									2,322	2,042	28
Operating income	50,424	28,602	62,795	33,019	41,170	15,903	51,773	19,081	174,840	127,927	136,959
Equity income									916	458	405
Other and income tax expense									(37,181)	(35,822)	(42,919)
Net income	$ 47,372	$ 21,247	$ 45,846	$ 24,110	$ 31,949	$ 9,643	$ 37,536	$ 13,435	138,575	92,563	94,445
Operating Segments [Member]
Segment Reporting [Line Items]
Revenues									515,875	481,097	467,403
Direct expenses, excluding depreciation and amortization									(56,026)	(57,884)	(54,008)
Selling, general and administrative expenses									(254,990)	(248,220)	(243,736)
Depreciation and amortization expenses									(42,032)	(44,536)	(43,280)
Impairment loss										(8,084)
Operating income									162,827	122,373	126,379
Segment Reconciling Items [Member]
Segment Reporting [Line Items]
Gain on disposition of property, plant and equipment									9,691	3,512	10,552
Foreign exchange gain									2,322	2,042	28
Core Auction [Member] | Operating Segments [Member]
Segment Reporting [Line Items]
Revenues									500,764	467,919	453,994
Direct expenses, excluding depreciation and amortization									(56,026)	(57,884)	(54,008)
Selling, general and administrative expenses									(241,274)	(233,438)	(227,402)
Depreciation and amortization expenses									(39,016)	(40,872)	(39,578)
Impairment loss										(8,084)
Operating income									164,448	127,641	133,006
EquipmentOne [Member] | Operating Segments [Member]
Segment Reporting [Line Items]
Revenues									15,111	13,178	13,409
Selling, general and administrative expenses									(13,716)	(14,782)	(16,334)
Depreciation and amortization expenses									(3,016)	(3,664)	(3,702)
Operating income									$ (1,621)	$ (5,268)	$ (6,627)