Comprehensive Income (Loss) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Changes in accumulated other comprehensive (loss) income by component, net of tax
Balance at the beginning of the period	$ 5,969,000	$ (1,775,000)	$ (2,476,000)	$ (1,622,000)
Other comprehensive income (loss)	(1,073,000)	2,966,000	7,372,000	2,813,000
Balance at the end of the period	4,896,000	1,191,000	4,896,000	1,191,000
Amounts reclassified from accumulated other comprehensive income (loss)			0	0
Investment Securities Available-for-Sale
Changes in accumulated other comprehensive (loss) income by component, net of tax
Balance at the beginning of the period	5,618,000	(1,886,000)	(2,827,000)	(1,733,000)
Other comprehensive income (loss)	(1,073,000)	2,966,000	7,372,000	2,813,000
Balance at the end of the period	4,545,000	1,080,000	4,545,000	1,080,000
Postretirement Benefits
Changes in accumulated other comprehensive (loss) income by component, net of tax
Balance at the beginning of the period	351,000	111,000	351,000	111,000
Other comprehensive income (loss)	0	0	0	0
Balance at the end of the period	$ 351,000	$ 111,000	$ 351,000	$ 111,000