Income Taxes - Summary of Activity in Total Valuation Allowances (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Balance at Beginning of Year	$ 1,434	$ 2,252	$ 12,066
Additions	0	0	0
Recoveries	(1,434)	(818)	(9,814)
Balance at End of Year	$ 1,434	$ 1,434	$ 2,252