Leasehold Improvements, Equipment and Construction in Progress, net (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Leasehold Improvements, Equipment and Construction in Progress, Net
Leasehold improvements, equipment and construction in progress, gross	$ 73,255	$ 48,520
Less accumulated depreciation and amortization	(34,917)	(31,788)
Leasehold improvements, equipment and construction in progress, net	38,338	16,732
Land	1,672
Leasehold improvements, equipment, land and construction in progress, net	40,010	16,732
Depreciation expense	6,280	4,167	3,722
Losses on sale and abandonment of leasehold improvements and equipment	80	31	53
Equipment
Leasehold Improvements, Equipment and Construction in Progress, Net
Leasehold improvements, equipment and construction in progress, gross	28,498	12,021
Equipment | Minimum
Leasehold Improvements, Equipment and Construction in Progress, Net
Ranges of Estimated useful life	2 years
Equipment | Maximum
Leasehold Improvements, Equipment and Construction in Progress, Net
Ranges of Estimated useful life	5 years
Software
Leasehold Improvements, Equipment and Construction in Progress, Net
Leasehold improvements, equipment and construction in progress, gross	15,031	12,643
Software | Minimum
Leasehold Improvements, Equipment and Construction in Progress, Net
Ranges of Estimated useful life	3 years
Software | Maximum
Leasehold Improvements, Equipment and Construction in Progress, Net
Ranges of Estimated useful life	10 years
Vehicles
Leasehold Improvements, Equipment and Construction in Progress, Net
Ranges of Estimated useful life	4 years
Leasehold Improvements, Equipment and Construction in Progress, Net
Leasehold improvements, equipment and construction in progress, gross	9,353	9,405
Other
Leasehold Improvements, Equipment and Construction in Progress, Net
Ranges of Estimated useful life	10 years
Leasehold Improvements, Equipment and Construction in Progress, Net
Leasehold improvements, equipment and construction in progress, gross	367	2,464
Leasehold improvements
Leasehold Improvements, Equipment and Construction in Progress, Net
Leasehold improvements, equipment and construction in progress, gross	17,920	9,732
Leasehold improvements | Maximum
Leasehold Improvements, Equipment and Construction in Progress, Net
Ranges of Estimated useful life	10 years
Construction in progress
Leasehold Improvements, Equipment and Construction in Progress, Net
Leasehold improvements, equipment and construction in progress, gross	$ 2,086	$ 2,255