Other employee benefits (Tables)

12 Months Ended

Dec. 31, 2017

Statement [Line Items]

Disclosure of additional information about other employee benefit plans [Table Text Block]

		Year ended
		December 31,
		2017			2016
Opening defined benefit obligation	$	89,005		$	80,259
Current service cost 1		2,614			2,579
Interest cost		3,567			3,367
Effects of movements in exchange rates		7,026			2,197
Remeasurement actuarial (gains)/losses:
Arising from changes in demographic assumptions		1,172			-
Arising from changes in financial assumptions		6,761			2,712
Arising from experience adjustments		(120	)		(160	)
Benefits paid		(2,196	)		(1,949	)
Closing defined benefit obligation	$	107,829		$	89,005

Disclosure of additional information about other employee benefit plans, balance by member group [Table Text Block]

		Dec 31, 2017		Dec 31, 2016
Active members	$	64,460	$	52,611
Inactive members		43,369		36,394
Closing defined benefit obligation	$	107,829	$	89,005

Disclosure of changes in fair value of assets of other employee benefits plan [Table Text Block]

		Dec. 31, 2017			Dec. 31, 2016
Employer contributions	$	2,196		$	1,949
Benefits paid		(2,196	)		(1,949	)
Closing fair value of assets	$	-		$	-

Disclosure of net benefit liability for other employee benefits [Table Text Block]

		Dec. 31,		Dec. 31,
		2017		2016
Unfunded benefit obligation	$	107,829	$	89,005
Vacation accrual and other - non-current		3,324		2,624
Net liability	$	111,153	$	91,629

Disclosure of detailed information about other employee benefits plan [Table Text Block]

		Dec. 31,		Dec. 31,
		2017		2016
Other employee benefits liability - current (note 13)	$	2,756	$	2,356
Other employee benefits liability - non-current		108,397		89,273
Net liability	$	111,153	$	91,629

Disclosure of detailed information about employee future benefit expense [Table Text Block]

		Dec. 31, 2017		Dec. 31, 2016
Current service cost 1	$	2,614	$	2,579
Net interest cost		3,567		3,367
Components recognized in consolidated income statements	$	6,181	$	5,946

Disclosure of detailed information about remeasurement of other long term employee benefits [Table Text Block]

		Dec. 31, 2017			Dec. 31, 2016
Remeasurement on the net defined benefit liability:
Actuarial (gains)/losses arising from changes in demographic assumptions	$	1,172		$	-
Actuarial (gains)/losses arising from changes in financial assumptions		6,761			2,712
Actuarial gains arising from changes experience adjustments		(120	)		(160	)
Components recognized in statements of comprehensive income	$	7,813		$	2,552
Total other employee future benefit cost	$	13,994		$	8,498

Disclosure of other employee benefit plan, assumptions used [Table Text Block]

	2017	2016
Defined benefit cost:
Discount rate	4.03 %	4.19%
Initial weighted average health care trend rate	6.13 %	6.28%
Ultimate weighted average health care trend rate	4.00 %	4.00%
Average longevity at retirement age for current pensioners (years) 1 :
Males	21.6	21.6
Females	24.1	24.0
	2017	2016
Defined benefit obligation:
Discount rate	3.64 %	4.03%
Initial weighted average health care trend rate	5.97 %	6.13%
Ultimate weighted average health care trend rate	4.00 %	4.00%
Average longevity at retirement age for current pensioners (years):
Males	21.0	21.6
Females	23.7	24.1
Average longevity at retirement age for current employees
(future pensioners) (years):
Males	22.9	23.0
Females	25.5	25.3