Financial Derivatives and Hedging Activities - Fair Value Amounts Recorded as Component of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Balance at January 1,	$ (5,640)	$ 1,882
Deferred (losses) gains on cash flow hedges	1,142	(6,455)
Reclassified to earnings	4,939	(1,687)
Balance at September 30,	$ 441	$ (6,260)

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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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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