SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Description
Balance at beginning of year	$ 6,934	$ 5,712	$ 5,190
Additions charged to expense	9,235	11,251	9,783
Deductions	8,882	10,029	9,261
Balance at End of Year	7,287	6,934	5,712
Reserve for bad debts
Description
Balance at beginning of year	1,337	1,128	1,197
Additions charged to expense	123	676	38
Deductions	352	467	107
Balance at End of Year	1,108	1,337	1,128
Reserve for cash discounts
Description
Balance at beginning of year	612	692	724
Additions charged to expense	8,504	9,482	9,122
Deductions	8,530	9,562	9,154
Balance at End of Year	586	612	692
Deferred tax asset valuation
Description
Balance at beginning of year	4,985	3,892	3,269
Additions charged to expense	608	1,093	623
Balance at End of Year	$ 5,593	$ 4,985	$ 3,892