Build-to-Suit Lease Obligation - Schedule of Expected Reductions (Increases) in Build-to-Suit Lease Obligation (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014
Leases [Abstract]
Build-to-Suit Lease Obligation, 2015	$ 698
Build-to-Suit Lease Obligation, 2016	(12)
Build-to-Suit Lease Obligation, 2017	66
Build-to-Suit Lease Obligation, 2018	150
Build-to-Suit Lease Obligation, 2019	241
Build-to-Suit Lease Obligation, 2020 and thereafter	18,266
Total minimum payments	$ 19,409