Income Taxes - Summary of Income Tax Examinations (Details)	12 Months Ended
	Dec. 31, 2015
Minimum | U.S. Internal Revenue Service
Income Tax Examination
Open Tax Year	2013
Minimum | New Zealand Inland Revenue
Income Tax Examination
Open Tax Year	2012
Maximum | U.S. Internal Revenue Service
Income Tax Examination
Open Tax Year	2016
Maximum | New Zealand Inland Revenue
Income Tax Examination
Open Tax Year	2016