Accounts payable and accrued expenses (Details) - USD ($) $ in Thousands	Apr. 01, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Outstanding checks in excess of cash	$ 11,111	$ 12,269
Accounts payable, trade	780,467	729,415
Accrued expenses	328,612	333,942
Product warranties	46,563	46,347
Accrued interest	6,794	20,396
Accrued compensation and benefits	156,794	193,213
Total accounts payable and accrued expenses	$ 1,330,341	$ 1,335,582