Furniture, Equipment and Leasehold Improvements, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Furniture, equipment and leasehold improvements [Abstract]
Furniture, equipment and leasehold improvements, gross	$ 841,046	$ 841,743
Less: Accumulated depreciation and amortization	(693,172)	(696,492)
Furniture, equipment and leasehold improvements, net	147,874	145,251
Furniture and equipment
Furniture, equipment and leasehold improvements [Abstract]
Furniture, equipment and leasehold improvements, gross	556,966	575,378
Leasehold improvements
Furniture, equipment and leasehold improvements [Abstract]
Furniture, equipment and leasehold improvements, gross	$ 284,080	$ 266,365