Other intangible assets (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Carrying amount:
Balance at beginning of period			$ 22,233,000
Foreign currency translation adjustment			212,000
Balance at end of period	22,445,000		22,445,000
Accumulated amortization:
Balance at beginning of period			2,226,000
Charge for the year			376,000
Foreign currency translation adjustment			20,000
Balance at end of period	2,622,000		2,622,000
Other information
Amortization expense	236,000	216,000	376,000	449,000
Net book value:
Net book value	19,823,000		19,823,000		20,007,000
Estimated amortization expense
2012			501,000
2013			501,000
2014			501,000
2015			501,000
2016			501,000
Favorable lease assets
Carrying amount:
Balance at beginning of period			13,503,000
Foreign currency translation adjustment			223,000
Balance at end of period	13,726,000		13,726,000
Accumulated amortization:
Balance at beginning of period			1,616,000
Charge for the year			27,700,000
Foreign currency translation adjustment			25,000
Balance at end of period	1,918,000		1,918,000
Other information
Amortization period, minimum (in years)			19
Amortization period, maximum (in years)			60
Net book value:
Net book value	11,808,000		11,808,000		11,887,000
Internet sites
Carrying amount:
Balance at beginning of period			1,630,000
Foreign currency translation adjustment			(11,000)
Balance at end of period	1,619,000		1,619,000
Accumulated amortization:
Balance at beginning of period			610,000
Charge for the year			99,000
Foreign currency translation adjustment			(5,000)
Balance at end of period	704,000		704,000
Other information
Amortization period (in years)			10
Net book value:
Net book value	915,000		915,000		1,020,000
Tradenames
Carrying amount:
Balance at beginning of period					7,100,000
Balance at end of period	7,100,000		7,100,000		7,100,000
Net book value:
Carrying amount	$ 7,100,000		$ 7,100,000		$ 7,100,000