Accumulated Other Comprehensive Income (Loss) - Summary of Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), Pre-Tax Amount	$ (147)	$ 158	$ (1,061)
Other comprehensive income (loss), Tax Expense (Benefit)	0	0	0
Other comprehensive income (loss) before reclassification adjustments, After-Tax Amount	(237)	(814)	(1,714)
Other comprehensive income (loss), Reclassification adjustments, After-Tax Amount	90	972	653
Other comprehensive income (loss)	(147)	158	(1,061)
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	(134)	(565)	(1,655)
Other comprehensive income (loss), Reclassification adjustments, Pre-Tax Amount	90	972	653
Other comprehensive income (loss), Pre-Tax Amount	(44)	407	(1,002)
Other comprehensive income (loss) before reclassification adjustments, Tax Expense (Benefit)	0	0	0
Other comprehensive income (loss), Reclassification adjustments, Tax Expense (Benefit)	0	0	0
Other comprehensive income (loss), Tax Expense (Benefit)	0	0	0
Other comprehensive income (loss) before reclassification adjustments, After-Tax Amount	(134)	(565)	(1,655)
Other comprehensive income (loss), Reclassification adjustments, After-Tax Amount	90	972	653
Other comprehensive income (loss)	(44)	407	(1,002)
Unrealized Gains (Losses) on Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassification adjustments, Pre-Tax Amount	(103)	(249)	(59)
Other comprehensive income (loss), Reclassification adjustments, Pre-Tax Amount	0	0	0
Other comprehensive income (loss), Pre-Tax Amount	(103)	(249)	(59)
Other comprehensive income (loss) before reclassification adjustments, Tax Expense (Benefit)	0	0	0
Other comprehensive income (loss), Reclassification adjustments, Tax Expense (Benefit)	0	0	0
Other comprehensive income (loss), Tax Expense (Benefit)	0	0	0
Other comprehensive income (loss) before reclassification adjustments, After-Tax Amount	(103)	(249)	(59)
Other comprehensive income (loss), Reclassification adjustments, After-Tax Amount	0	0	0
Other comprehensive income (loss)	$ (103)	$ (249)	$ (59)