Shareholders' equity (Share repurchase program textuals) (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	1 Months Ended	3 Months Ended
	Aug. 26, 2017	Sep. 30, 2017	Oct. 01, 2016
Shareholders' equity
Authorized repurchase of common stock under Share Repurchase Program		$ 1,750,000
Shares repurchased during period (in shares)		1.9
Cost of repurchase		$ 72,100
Cash dividends paid per common share	$ 0.18	$ 0.18	$ 0.17
Dividends paid on common stock		$ 22,012	$ 21,676