Supplemental cash flow information (Tables)

12 Months Ended

Dec. 31, 2017

Supplemental Cash Flow Elements [Abstract]

Schedule of supplemental cash flow information

	2017	2016	2015
Year ended December 31,	$’000	$’000	$’000
Cash paid during the period for:
Interest	30,329	40,930	27,828
Income taxes, net of refunds	19,838	19,804	18,306