Fixed Assets (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Fixed assets, gross	$ 60,708,000	$ 34,412,000
Less: Accumulated depreciation	(21,440,000)	(18,312,000)
Fixed assets, net	39,268,000	16,100,000
Depreciation expense	3,900,000	2,900,000	3,600,000
Furniture, fixtures and equipment [Member]
Property, Plant and Equipment [Line Items]
Fixed assets, gross	23,267,000	10,437,000
Computer software [Member]
Property, Plant and Equipment [Line Items]
Estimated life	3 years
Fixed assets, gross	2,237,000	2,685,000
Computer hardware [Member]
Property, Plant and Equipment [Line Items]
Estimated life	3 years
Fixed assets, gross	3,469,000	2,130,000
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Fixed assets, gross	$ 31,735,000	$ 19,160,000
Minimum [Member] | Furniture, fixtures and equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated life	3 years
Minimum [Member] | Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated life	5 years
Maximum [Member] | Furniture, fixtures and equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated life	7 years
Maximum [Member] | Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated life	15 years