SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Description
Balance at beginning of year	$ 4,302	$ 4,446	$ 2,999
Additions charged to expense	9,321	9,544	11,217
Deductions	9,422	9,688	9,770
Balance at End of Year	4,201	4,302	4,446
Reserve for bad debts
Description
Balance at beginning of year	1,410	1,300	1,398
Additions charged to expense		267	29
Reductions credited to expense	(166)
Deductions	19	157	127
Balance at End of Year	1,225	1,410	1,300
Reserve for cash discounts
Description
Balance at beginning of year	815	668	644
Additions charged to expense	9,247	9,678	9,667
Deductions	9,403	9,531	9,643
Balance at End of Year	659	815	668
Deferred tax asset valuation
Description
Balance at beginning of year	2,077	2,478	957
Additions charged to expense	240		1,521
Reductions credited to expense		(401)
Balance at End of Year	$ 2,317	$ 2,077	$ 2,478