Accounts payable and accrued expenses (Details) - USD ($) $ in Thousands	Apr. 02, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Outstanding checks in excess of cash	$ 12,327	$ 14,023
Accounts payable, trade	751,271	696,974
Accrued expenses	281,278	293,867
Product warranties	37,254	35,516
Accrued interest	7,404	34,623
Accrued compensation and benefits	157,955	181,022
Total accounts payable and accrued expenses	$ 1,247,489	$ 1,256,025