Schedule II - Valuation and Qualifying Accounts (Details) - Allowance for Ship and Debit Credits [Member] - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period		$ 39,486	$ 38,075	$ 34,415
Charged to Costs and Expenses		242,068	273,492	262,501
Deductions	[1]	(241,436)	(272,081)	(258,841)
Balance at End of Period		$ 40,118	$ 39,486	$ 38,075

[1] Deductions relate to ship and debit credits issued which adjust the sales price from the standard distribution price to the pre-approved lower price. Refer to Note 2, Significant Accounting Policies and Recent Accounting Pronouncements, for the Company’s revenue recognition policy, including the Company’s accounting for ship and debit claims.