Fair Value Measurements (Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2026	Dec. 31, 2025
Assets:
Cash and cash equivalents	$ 938,215	$ 734,553
Restricted cash	6,939	35,641
Restricted investments	270,884	228,959
Investments in lieu of retention	233,962	186,991
Total	$ 1,450,000	1,186,144
Cash and cash equivalents maturity period (maximum)	3 months
Level 1
Assets:
Cash and cash equivalents	$ 938,215	734,553
Restricted cash	6,939	35,641
Restricted investments	0	0
Investments in lieu of retention	38,152	27,849
Total	983,306	798,043
Level 1 \| Money Market Funds
Assets:
Investments in lieu of retention	38,200	27,800
Level 2
Assets:
Cash and cash equivalents	0	0
Restricted cash	0	0
Restricted investments	270,884	228,959
Investments in lieu of retention	195,810	159,142
Total	466,694	388,101
Level 2 \| Debt Securities
Assets:
Investments in lieu of retention	195,800	159,100
Level 3
Assets:
Cash and cash equivalents	0	0
Restricted cash	0	0
Restricted investments	0	0
Investments in lieu of retention	0	0
Total	$ 0	$ 0