Intangible assets, net (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Intangible assets, net
Accumulated amortization	$ (20,486)		$ (11,894)
Intangible assets, net	188,752		197,344
Amortization expense	3,957	78
Covenant not to compete
Intangible assets, net
Intangible assets	3,533		3,533
Trade names
Intangible assets, net
Intangible assets	9,820		9,820
Proprietary know how
Intangible assets, net
Intangible assets	34,650		34,650
Lease contract rights
Intangible assets, net
Intangible assets	80,235		80,235
Amortization expense	3,745	0
Management contract rights
Intangible assets, net
Intangible assets	$ 81,000		$ 81,000