Revenue from Contracts with Customers Changes in Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Receivables [Abstract]
Accounts Receivable, Allowance for Credit Loss, Current	$ 824	$ 1,423	$ 1,224
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	(167)	271
Allowance for Doubtful Accounts Receivable, Write-offs	$ (432)	$ (72)