Schedule II - Valuation and Qualifying Accounts (Tables)

12 Months Ended

Dec. 31, 2020

Notes Tables

Summary of Allowance for Doubtful Accounts and Revenue Adjustments [Table Text Block]

	2020			2019			2018
Balance at beginning of year	$	486		$	564		$	652
Provision for (reversal of) bad debt		13			(52	)		(50	)
Write-offs, net of recoveries		(15	)		(26	)		(38	)
Balance at end of year	$	484		$	486		$	564