Accounts payable and accrued expenses (Details) - USD ($) $ in Thousands	Sep. 28, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Outstanding checks in excess of cash	$ 4,064	$ 14,624
Accounts payable, trade	964,098	811,879
Accrued expenses	490,094	430,431
Product warranties	46,984	47,511
Accrued interest	12,293	21,908
Accrued compensation and benefits	221,326	197,513
Total accounts payable and accrued expenses	$ 1,738,859	$ 1,523,866