CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Restricted cash and cash equivalents
Restricted cash and cash equivalents	$ 49,227	$ 51,253
Restricted investments, short-term and long-term
Short-term restricted investments	88,867	82,772
Long term restricted investments	1,026	2,307
Other current restricted assets
Other current restricted assets	$ 43,547	$ 36,215
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)	55,549	54,285
Common stock, outstanding (in shares)	25,887	24,623
Treasury stock
Treasury stock (in shares)	29,662	29,662