Description of Business and Significant Accounting Policies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning balance	$ 1,856	$ 1,947	$ 1,405
Additions	368	17	670
Deductions	(1,133)	(108)	(128)
Ending balance	$ 1,091	$ 1,856	$ 1,947