Accumulated Other Comprehensive Income (Loss) - Summary of Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), Pre-Tax Amount	$ 2,730	$ 1,671
Other comprehensive income (loss), Tax Expense (Benefit)	(973)	(586)
Other comprehensive income (loss) before reclassification adjustments, After-Tax Amount	1,958	891
Other comprehensive income (loss), Reclassification adjustments, After-Tax Amount	(201)	194
Other comprehensive income (loss)	1,757	1,085
Unrealized Gains (Losses) on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassification adjustments, Pre-Tax Amount	2,887	1,217
Other comprehensive income (loss), Reclassification adjustments, Pre-Tax Amount	(201)	194
Other comprehensive income (loss), Pre-Tax Amount	2,686	1,411
Other comprehensive income (loss) before reclassification adjustments, Tax Expense (Benefit)	(957)	(495)
Other comprehensive income (loss), Reclassification adjustments, Tax Expense (Benefit)	0	0
Other comprehensive income (loss), Tax Expense (Benefit)	(957)	(495)
Other comprehensive income (loss) before reclassification adjustments, After-Tax Amount	1,930	722
Other comprehensive income (loss), Reclassification adjustments, After-Tax Amount	(201)	194
Other comprehensive income (loss)	1,729	916
Unrealized Gains (Losses) on Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassification adjustments, Pre-Tax Amount	44	260
Other comprehensive income (loss), Pre-Tax Amount	44	260
Other comprehensive income (loss) before reclassification adjustments, Tax Expense (Benefit)	(16)	(91)
Other comprehensive income (loss), Tax Expense (Benefit)	(16)	(91)
Other comprehensive income (loss) before reclassification adjustments, After-Tax Amount	28	169
Other comprehensive income (loss), Reclassification adjustments, After-Tax Amount	0	0
Other comprehensive income (loss)	$ 28	$ 169