Furniture, Equipment and Leasehold Improvements (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Furniture and Office Equipment	$ 20,484	$ 14,678
Leasehold Improvements	52,253	45,489
Computer and Computer-related Equipment	17,899	16,340
Total	90,636	76,507
Less: Accumulated Depreciation and Amortization	(42,656)	(33,980)
Furniture, Equipment and Leasehold Improvements, Net	$ 47,980	$ 42,527