Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accrued Liabilities [Abstract]
Commissions	$ 12,079	$ 12,025
Warranty	10,183	9,537	$ 14,336	$ 9,755
Accrued dividend	30,436	25,032
Billings in excess of cost	5,464	14,135
Customer deposits	15,094	16,392
Interest	19,776	18,275
Rebates	16,511	12,968
Other	58,970	52,374
Total	$ 168,513	$ 160,738