Organization and Significant Accounting Policies - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at January 1	$ 1,411	$ 1,545	$ 1,569
Provision charged to expense	573	0	0
Write-offs / Recoveries	(168)	(134)	(24)
Balance at December 31	$ 1,816	$ 1,411	$ 1,545