CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Restricted cash and cash equivalents
Restricted cash and cash equivalents	$ 79,746	$ 49,227
Restricted investments, short-term and long-term
Short-term restricted investments	101,884	88,867
Long term restricted investments	0	1,026
Other current restricted assets
Other current restricted assets	$ 74,385	$ 43,547
Preferred stock
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	10,000	10,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	100,000	100,000
Common stock, issued (in shares)	55,994	55,549
Common stock, outstanding (in shares)	26,332	25,887
Treasury stock
Treasury stock (in shares)	29,662	29,662