Other Comprehensive Income (Loss) (Reclassification Adjustments Out of Accumulated Other Comprehensive Income) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015		Sep. 30, 2014
Unrealized gains/(losses) on investments available-for-sale Affected line item in the Statements of Income:
Investment securities gains	$ 1	$ 8	$ 20		$ 8
Income before taxes			20		8
Tax expense			8		3
Net income			12		5
Amortization of defined benefit pension plan items Affected line item in the Statements of Income:
Recognized actuarial loss	$ 240	$ 67	791	[1]	183	[1]
Income before taxes			791		183
Tax expense			323		81
Net income			$ 468		$ 102

[1] This amount is included in the computation of net periodic benefit cost, see Note 9