Debt - Summary of Gain (Loss) Recognized On Interest Rate Derivative Designated As Cash Flow Hedges (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Debt Disclosure [Abstract]
Amount of gain (loss) recognized in other comprehensive income (loss)	$ 761	$ (726)	$ 2,470	$ (356)
Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) into interest expense	26	(233)	(52)	(233)
Total change in accumulated other comprehensive income (loss)	$ 735	$ (493)	$ 2,522	$ (123)

Amount after tax of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Balance Type:	debit
Period Type:	duration