Schedule of Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Change in net unrealized Gain during period:
Change in net unrealized gain during period, before tax amount	$ 931	$ 2,781	$ (175)	$ 24,200
Change in net unrealized gain during period, tax expense (benefit)	366	1,094	(69)	9,522
Change in net unrealized gain during period, net of tax amount	565	1,687	(106)	14,678
Reclassification adjustment for gains included in net income:
Reclassification adjustment for gains included in net income, before tax amount	(66)	(38)	(295)	(56)
Reclassification adjustment for gains included in net income, tax expense (benefit)	(26)	(15)	(116)	(22)
Reclassification adjustment for gains included in net income, net of tax amount	(40)	(23)	(179)	(34)
Change in net actuarial loss:
Change in net actuarial loss, before tax amount	35	35	102	104
Change in net actuarial loss, tax expense (benefit)	14	14	40	41
Change in net actuarial loss, net of tax amount	21	21	62	63
Other comprehensive income (loss):
Other comprehensive income (loss), before tax	900	2,778	(368)	24,248
Total other comprehensive income, tax expense (benefit)	354	1,093	(145)	9,541
Total other comprehensive income, net of tax amount	$ 546	$ 1,685	$ (223)	$ 14,707