Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ (323)	[1]
Other comprehensive income before reclassifications	(2,985)
Amounts reclassified from accumulated other comprehensive income	(1,592)
Net current period other comprehensive income	(4,577)		730
Ending balance	(4,900)
Unrealized gains (losses) on available for sale securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	3,650
Other comprehensive income before reclassifications	(2,985)
Amounts reclassified from accumulated other comprehensive income	(1,438)
Net current period other comprehensive income	(4,423)
Ending balance	(773)
Defined benefit plan items [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(3,973)
Other comprehensive income before reclassifications	0
Amounts reclassified from accumulated other comprehensive income	(154)
Net current period other comprehensive income	(154)
Ending balance	$ (4,127)

[1] Derived from audited consolidated financial statements