Furniture, Equipment and Leasehold Improvements - Schedule of Furniture, Equipment and Leasehold Improvements (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Total Furniture, Equipment and Leasehold Improvements	$ 58,833	$ 54,454
Accumulated Depreciation	(22,922)	(19,649)
Furniture, Equipment and Leasehold Improvements, Net	35,911	34,805
Office Equipment
Property Plant And Equipment [Line Items]
Total Furniture, Equipment and Leasehold Improvements	2,285	2,151
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total Furniture, Equipment and Leasehold Improvements	41,821	38,745
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total Furniture, Equipment and Leasehold Improvements	$ 14,727	$ 13,558