Supplemental Comprehensive Income Disclosures (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Supplemental Comprehensive Income Disclosures [Abstract]
Unrealized holding gains on securities arising during the period	$ (28,071)	$ 998	$ (32,346)	$ 1,097
Non-credit related gains (losses) on securities not expected to be sold	2,841	(1,323)	4,705	175
Reclassification adjustment for gains on securities included in net income	(4)	0	(8)	0
Total available for sale securities	(25,234)	(325)	(27,649)	1,272
Total other comprehensive income	(25,234)	(325)	(27,649)	1,272
Unrealized holding gains on securities arising during the period	9,817	(344)	11,312	(378)
Non-credit related gains (losses) on securities not expected to be sold	(995)	463	(1,647)	(61)
Reclassification adjustment for gains on securities included in net income	2	0	3	0
Total available for sale securities	8,824	119	9,668	(439)
Total other comprehensive income	8,824	119	9,668	(439)
Unrealized holding gains on securities arising during the period	(18,254)	654	(21,034)	719
Non-credit related gains (losses) on securities not expected to be sold	1,846	(860)	3,058	114
Reclassification adjustment for gains on securities included in net income	(2)	0	(5)	0
Total available for sale securities	(16,410)	(206)	(17,981)	833
Other comprehensive income (loss)	$ (16,410)	$ (206)	$ (17,981)	$ 833