Other Comprehensive Income (Loss) (Net Accumulated Other Comprehensive Income (Loss)) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ (823)	$ (2,970)	$ 11,312
Total other comprehensive income (loss)	(474)	2,147	(14,282)
Ending Balance	(1,297)	(823)	(2,970)
Unrealized Gains (Losses) on Investments Available-for-Sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	8,078	358	20,258
Total other comprehensive income (loss)	(1,512)	7,720	(19,900)
Ending Balance	6,566	8,078	358
Defined Benefit Pension Plan
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(8,901)	(3,328)	(8,946)
Total other comprehensive income (loss)	1,038	(5,573)	5,618
Ending Balance	$ (7,863)	$ (8,901)	$ (3,328)