Segment and Geographical Information - Schedule of Geographical Operating Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales	$ 239,722	$ 184,419	$ 200,964	$ 194,491	$ 229,302	$ 176,867	$ 269,171	$ 140,575	$ 819,596	$ 815,915	$ 568,800
Operating Income									215,491	255,777	77,784
Identifiable Assets	2,858,481				2,685,760				2,858,481	2,685,760
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales									419,403	528,344	324,552
Operating Income									138,528	220,703	73,749
Identifiable Assets	2,331,230				2,181,658				2,331,230	2,181,658
New Zealand
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales									400,193	287,571	244,248
Operating Income									76,963	35,074	$ 4,035
Identifiable Assets	$ 527,251				$ 504,102				$ 527,251	$ 504,102