Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 3,478	$ 4,921	$ 8,261	$ 9,943
Available-for-sale investment securities:
Gross unrealized holding gain (loss) arising in the period	7,258	(16,727)	15,898	(16,270)
Related tax (expense) benefit	(2,541)	5,854	(5,565)	5,694
Less: reclassification adjustment for net gain included in net income	66	26	36	444
Related tax expense	(24)	(9)	(13)	(155)
Net effect on other comprehensive income (loss)	4,675	(10,890)	10,310	(10,865)
Defined benefit plans:
Net loss arising during the period	(126)	0	(1,179)	0
Related tax benefit	43	0	413	0
Amortization of unrecognized loss and service cost on benefit plans	34	52	65	97
Related tax expense	(12)	(18)	(23)	(34)
Recognition of loss due to settlement and curtailment	536	0	1,022	0
Related tax expense	(188)	0	(358)	0
Net effect on other comprehensive income (loss)	287	34	(60)	63
Total other comprehensive income (loss), net of tax	4,962	(10,856)	10,250	(10,802)
Total comprehensive income (loss)	$ 8,440	$ (5,935)	$ 18,511	$ (859)