Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Allowance for credit losses	$ 1,477	$ 3,469
Shareholders' equity:
Common stock, par value (USD per share)	$ 0	$ 0
Common stock, shares authorized	240,000,000	240,000,000
Common stock, shares issued	151,124,000	150,341,000