Debt - Schedule of Net Interest Expense (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Interest Income Expense Net [Abstract]
Interest expense									$ 12,542	$ 11,104	$ 9,998
Interest income									(262)	(57)	(112)
Interest expense net of interest income									12,280	11,047	9,886
Capitalized interest									(839)	(689)	(287)
Interest expense, net	$ 2,617	$ 2,846	$ 3,021	$ 2,957	$ 2,863	$ 2,987	$ 2,329	$ 2,179	$ 11,441	$ 10,358	$ 9,599