Insurance Recoveries (Narrative) (Details) NZD in Thousands, $ in Thousands	1 Months Ended				9 Months Ended		12 Months Ended
	May 31, 2017 NZD	May 31, 2017 USD ($)	Apr. 30, 2017 NZD	Apr. 30, 2017 USD ($)	Sep. 30, 2017 NZD	Sep. 30, 2017 USD ($)	Dec. 31, 2016 NZD	Dec. 31, 2016 USD ($)
Insurance Recoveries [Abstract]
Insurance coverage limit			NZD 36,000	$ 25,000
Proceeds from insurance settlement	NZD 28,900	$ 20,000					NZD 7,100	$ 5,000
Total insurance gains					NZD 14,849	$ 10,740