Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Allowance for doubtful accounts	$ 930	$ 2,092
Stockholders' equity:
Preferred stock, par value (in dollars per share)	$ 25	$ 25
Preferred stock, shares authorized (in shares)	2,000,000	2,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0667	$ 0.0667
Common stock, shares authorized (in shares)	120,000,000	120,000,000
Common stock, shares issued (in shares)	32,467,909	32,448,705
Common stock, shares outstanding (in shares)	32,382,637	32,372,621
Treasury stock (in shares)	85,272	76,084