Schedule II - Consolidated Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance For Doubtful Accounts And Sales Allowances [Member]
Valuation and Qualifying Accounts Roll Forward]
Balance at beginning of year	$ 13,694	$ 14,992	$ 15,976
Additions charged to costs and expenses	1,536	2,357	1,350
Deductions	(4,128)	(3,355)	(2,992)
Other changes	1,302	(300)	658
Balance at end of year	12,404	13,694	14,992
Reserve for inventory obsolescence [Member]
Valuation and Qualifying Accounts Roll Forward]
Balance at beginning of year	38,879	43,452	41,967
Additions charged to costs and expenses	8,616	8,621	11,360
Deductions	(9,049)	(11,833)	(9,696)
Other changes	(4,406)	(1,361)	(179)
Balance at end of year	$ 34,040	$ 38,879	$ 43,452