Accumulated Other Comprehensive Income (Loss) (Schedule of Balances of Accumulated Other Comprehensive Income (Loss)) (Detail) - USD ($) $ in Thousands	3 Months Ended					6 Months Ended
	Jun. 30, 2019		Jun. 30, 2018		Mar. 31, 2018	Jun. 30, 2019		Jun. 30, 2018
Unrealized gains (losses) on available-for-sale securities	$ 0	[1]	$ 0	[1]	$ (1,181)	$ 0	[1]	$ (1,181)	[1]
Other Comprehensive Income (Loss), Net of Tax	$ 0		$ 0			$ 0		$ (1,181)
AOCI Attributable to Parent [Member]
Unrealized gains (losses) on available-for-sale securities					$ (1,181)

[1] Net of tax of