Leasehold Improvements, Equipment and Construction in Progress, Net (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Leasehold Improvements, Equipment and Construction in Progress, Net
Leasehold improvements, equipment and construction in progress, gross	$ 49,345		$ 49,345		$ 48,520
Less accumulated depreciation and amortization	(32,928)		(32,928)		(31,788)
Leasehold improvements, equipment and construction in progress, net	16,417		16,417		16,732
Depreciation expense	1,121	1,016	2,163	1,947
(Gains) losses on sale and abandonment of leasehold improvements and equipment	44	(47)	48	(36)
Equipment
Leasehold Improvements, Equipment and Construction in Progress, Net
Leasehold improvements, equipment and construction in progress, gross	12,097		12,097		12,021
Equipment | Minimum
Leasehold Improvements, Equipment and Construction in Progress, Net
Ranges of Estimated useful life (in years)			2 years
Equipment | Maximum
Leasehold Improvements, Equipment and Construction in Progress, Net
Ranges of Estimated useful life (in years)			5 years
Software
Leasehold Improvements, Equipment and Construction in Progress, Net
Leasehold improvements, equipment and construction in progress, gross	13,144		13,144		12,643
Software | Minimum
Leasehold Improvements, Equipment and Construction in Progress, Net
Ranges of Estimated useful life (in years)			3 years
Software | Maximum
Leasehold Improvements, Equipment and Construction in Progress, Net
Ranges of Estimated useful life (in years)			10 years
Vehicles
Leasehold Improvements, Equipment and Construction in Progress, Net
Ranges of Estimated useful life (in years)			4 years
Leasehold Improvements, Equipment and Construction in Progress, Net
Leasehold improvements, equipment and construction in progress, gross	9,199		9,199		9,405
Other
Leasehold Improvements, Equipment and Construction in Progress, Net
Ranges of Estimated useful life (in years)			10 years
Leasehold Improvements, Equipment and Construction in Progress, Net
Leasehold improvements, equipment and construction in progress, gross	2,503		2,503		2,464
Leasehold improvements
Leasehold Improvements, Equipment and Construction in Progress, Net
Leasehold improvements, equipment and construction in progress, gross	9,386		9,386		9,732
Leasehold improvements | Maximum
Leasehold Improvements, Equipment and Construction in Progress, Net
Ranges of Estimated useful life (in years)			10 years
Construction in progress
Leasehold Improvements, Equipment and Construction in Progress, Net
Leasehold improvements, equipment and construction in progress, gross	$ 3,016		$ 3,016		$ 2,255