Accounts payable and accrued expenses (Details) - USD ($) $ in Thousands	Oct. 01, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Outstanding checks in excess of cash	$ 12,101	$ 14,023
Accounts payable, trade	767,248	696,974
Accrued expenses	398,759	293,867
Product warranties	37,506	35,516
Accrued interest	12,085	34,623
Accrued compensation and benefits	207,370	181,022
Total accounts payable and accrued expenses	$ 1,435,069	$ 1,256,025