Other Comprehensive Income (Loss) (Net Accumulated Other Comprehensive Income (Loss)) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			$ (823)	$ (2,970)
Other comprehensive income before reclassification, net of tax			(100)	8,148
Reclassifications from accumulated other comprehensive income, net of tax			331	55
Total other comprehensive income (loss)	$ (2,738)	$ 3,883	231	8,203
Ending Balance	(592)	5,233	(592)	5,233
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			(100)	8,148
Reclassifications from accumulated other comprehensive income, net of tax			0	0
Total other comprehensive income (loss)			(100)	8,148
Ending Balance	7,978	8,506	7,978	8,506
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			331	55
Total other comprehensive income (loss)			331	55
Ending Balance	$ (8,570)	$ (3,273)	$ (8,570)	$ (3,273)