Fair Value Disclosures - Assets Measured at Fair Value on a Non-recurring Basis (Details 3) (Fair Value, Measurements, Nonrecurring [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Assets measured at fair value on a non-recurring basis
Impaired loans held for investment	$ 44,976	$ 39,948
Mortgage servicing rights	4,152	2,739
Other real estate owned	1,607	6,600
Total assets	50,735	49,287
Level 1 [Member]
Assets measured at fair value on a non-recurring basis
Impaired loans held for investment
Mortgage servicing rights
Other real estate owned
Total assets
Level 2 [Member]
Assets measured at fair value on a non-recurring basis
Impaired loans held for investment
Mortgage servicing rights	4,152	2,739
Other real estate owned	1,607	6,600
Total assets	5,759	9,339
Level 3 [Member]
Assets measured at fair value on a non-recurring basis
Impaired loans held for investment	44,976	39,948
Mortgage servicing rights
Other real estate owned
Total assets	$ 44,976	$ 39,948