Comprehensive Income and Accumulated Other Comprehensive Income - Schedule of Changes in Accumulated Other Comprehensive Income (AOCI) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Beginning balance	$ 2,052	$ 1,961	$ 2,810	$ (4,295)
Other comprehensive income/(loss) before reclassification	1,400	121	(188)	6,192
Amounts reclassified from accumulated other comprehensive income	(92)	(4)	738	181
Net current period other comprehensive income/(loss)	1,308	117	550	6,373
Ending balance	$ 3,360	$ 2,078	$ 3,360	$ 2,078