Intangible assets, net (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Intangible assets, net
Accumulated amortization	$ (11,894)	$ (846)
Total	197,344	1,358
Expected future amortization of intangible assets
2013	31,538
2014	27,105
2015	24,828
2016	23,168
2017	13,729
2018 and Thereafter	76,976
Total	197,344	1,358
Amortization expense	4,024	260	2,173
Covenant not to compete
Intangible assets, net
Intangible assets	3,533	834
Trade names
Intangible assets, net
Intangible assets	9,820	720
Proprietary know how
Intangible assets, net
Intangible assets	34,650	650
Lease contract rights
Intangible assets, net
Intangible assets	80,235
Expected future amortization of intangible assets
Amortization expense	1,435	0	0
Management contract rights
Intangible assets, net
Intangible assets	$ 81,000