Build-to-Suit Lease Obligation - Schedule of Expected Reductions (Increases) in Build-to-Suit Lease Obligation (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015
Leases [Abstract]
Build-to-Suit Lease Obligation, Remainder of 2015	$ 473
Build-to-Suit Lease Obligation, 2016	(1)
Build-to-Suit Lease Obligation, 2017	77
Build-to-Suit Lease Obligation, 2018	162
Build-to-Suit Lease Obligation, 2019	254
Build-to-Suit Lease Obligation, 2020 and after	18,744
Total minimum payments	$ 19,709