Property, plant and equipment (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Property, plant and equipment
Property, plant and equipment, gross	$ 1,444,891,000		$ 1,444,891,000		$ 1,376,894,000
Less: Accumulated depreciation	(297,148,000)		(297,148,000)		(269,237,000)
Property, plant and equipment, net	1,147,743,000		1,147,743,000		1,107,657,000
Depreciation charge on property, plant and equipment	10,425,000	11,732,000	31,225,000	34,613,000
Capitalized interest recorded in property, plant and equipment	1,003,000	0	2,905,000	0	863,000
Charleston Center LLC
Property, plant and equipment
Property, plant and equipment, net	184,418,000		184,418,000		185,788,000
Land and buildings
Property, plant and equipment
Property, plant and equipment, gross	1,041,874,000		1,041,874,000		992,748,000
Machinery and equipment
Property, plant and equipment
Property, plant and equipment, gross	189,947,000		189,947,000		181,467,000
Fixtures, fittings and office equipment
Property, plant and equipment
Property, plant and equipment, gross	194,877,000		194,877,000		184,618,000
River cruise ship and canal boats
Property, plant and equipment
Property, plant and equipment, gross	18,193,000		18,193,000		18,061,000
Casa de Sierra Nevada San Miguel de Allende [Member]
Property, plant and equipment
Impairment of Long-Lived Assets Held-for-use		$ 2,000,000