Supplemental Cash Flow Information (Schedule Of Net Changes In Operating Assets And Liabilities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Supplemental Cash Flow Information [Abstract]
Restricted cash	$ (102)	$ 22,347	$ (41,001)
Trade and other receivables	12,757	(113)	(9,163)
Inventory	(17,635)	4,109	8,905
Advances against auction contracts	20,804	(14,230)	(4,843)
Prepaid expenses and deposits	(307)	(3,873)	6,818
Income taxes receivable	742	(958)	5,485
Auction proceeds payable	5,151	(3,855)	40,246
Trade and other payables	(7,654)	13,826	901
Income taxes payable	3,481	2,408	2,482
Share unit liabilities	5,397	5,699	2,460
Other	2,398	(4,810)	(1,773)
Net changes in operating assets and liabilities	$ 25,032	$ 20,550	$ 10,517