Organization and Summary of Significant Accounting Policies Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	$ 4,205	$ 4,008	$ 4,547
Bad debt expense	1,199	1,110	1,167
Write-offs, net of recoveries	(1,354)	(913)	(1,706)
Balance at end of year	4,050	4,205	4,008
Inventory Valuation Reserve [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	6,979	6,403	7,103
Provision for inventory write-downs	2,036	3,043	1,535
Deductions for inventory write-offs	(2,484)	(2,467)	(2,235)
Balance at end of year	$ 6,531	$ 6,979	$ 6,403