Other Comprehensive Income (Loss) (Net Accumulated Other Comprehensive Income (Loss)) (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) [Line Items]
Beginning Balance			$ (823)	$ (2,970)
Other comprehensive income before reclassification, net of tax			2,144	6,495
Reclassifications from accumulated other comprehensive income, net of tax			480	107
Total other comprehensive income (loss)	$ 2,393	$ (1,601)	2,624	6,602
Ending Balance	1,801	3,632	1,801	3,632
Unrealized Gains (Losses) on Investments Available-for-Sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			8,078	358
Other comprehensive income before reclassification, net of tax			2,144	6,495
Reclassifications from accumulated other comprehensive income, net of tax			12	5
Total other comprehensive income (loss)			2,156	6,500
Ending Balance	10,234	6,858	10,234	6,858
Defined Benefit Pension Plan
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(8,901)	(3,328)
Other comprehensive income before reclassification, net of tax			0	0
Reclassifications from accumulated other comprehensive income, net of tax			468	102
Total other comprehensive income (loss)			468	102
Ending Balance	$ (8,433)	$ (3,226)	$ (8,433)	$ (3,226)