Income taxes (Tables)

9 Months Ended

Sep. 30, 2019

Income Tax Disclosure [Abstract]

Provision for income taxes

Provision for income taxes is based on the following:

	For Three Months Ended						For Nine Months Ended
	September 30,						September 30,
	2019			2018			2019			2018
Taxes calculated using the estimated annual effective tax rate	$	257		$	367		$	715		$	1,027
Discrete tax items	(102)			(13)			(191)			(185)
Provision for income taxes	$	155		$	354		$	524		$	842
Actual effective tax rate	10		%	18		%	12		%	16		%