Accounts payable and accrued expenses (Components of accounts payable and accrued expenses) (Details) - USD ($) $ in Thousands	Jul. 04, 2015	Dec. 31, 2014
Payables and Accruals [Abstract]
Outstanding checks in excess of cash	$ 21,820	$ 16,083
Accounts payable, trade	727,676	622,360
Accrued expenses	323,170	269,668
Product warranties	39,474	29,350
Accrued interest	28,914	28,365
Accrued compensation and benefits	162,433	138,683
Total accounts payable and accrued expenses	$ 1,303,487	$ 1,104,509