Leases - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Lessee, Lease, Description
Operating lease, liability, including sublease receivables	$ 672,900		$ 705,100
Operating lease, liability	663,172		694,916
Operating lease, liability, portion ring-fenced by special purpose vehicles	36,600		36,600
Operating lease, future contracted revenues and sublease income	202,300		$ 179,300
Operating lease costs	33,500	$ 33,900
Operating lease payments	31,800	29,900
Short-term lease expense	400	200
Sublease income	$ 600	800
Weighted average discount rate	4.94%		4.87%
Weighted average lease term	6 years 3 months 18 days		6 years 6 months
Right-of-use assets	$ 568,118		$ 596,362
Right-of-use liabilities	$ 104,891		$ 107,084
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accounts payable, accrued expenses and other liabilities (see Note 26)		Accounts payable, accrued expenses and other liabilities (see Note 26)
Right-of-use liabilities, non-current	$ 568,044		$ 598,044
Rent expense	41,700	$ 39,500
Management services, servicing fees and other
Lessee, Lease, Description
Operating lease, liability	$ 159,200		$ 172,700
Minimum
Lessee, Lease, Description
Remaining lease terms	1 year
Options to extend leases	1 year
Maximum
Lessee, Lease, Description
Remaining lease terms	11 years
Options to extend leases	10 years