Capitalized Interest - Summary of Interest Costs Incurred, Capitalized, Expensed and Charged to Cost of Sales (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Interest Costs Incurred Capitalized [Abstract]
Interest capitalized, beginning of period	$ 4,332	$ 3,810	$ 4,072	$ 3,294
Interest incurred	6,317	6,293	18,842	18,716
Interest charged to interest expense	(6,081)	(5,775)	(17,955)	(17,292)
Interest charged to cost of sales	(288)	(301)	(679)	(691)
Interest capitalized, end of period	$ 4,280	$ 4,027	$ 4,280	$ 4,027