Loans and the Allowance for Loan Losses (Details 10) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Changes in accretable yield of loans acquired with deteriorated credit quality
Balance at January 1, 2012	$ (10,543)
Reclasses from nonaccretable difference	(13,194)
Accretion	14,602
Balance at September 30, 2012	(9,135)
Impaired Covered Loans [Member]
Changes in accretable yield of loans acquired with deteriorated credit quality
Balance at January 1, 2012	(40)
Reclasses from nonaccretable difference	(844)
Accretion	868
Balance at September 30, 2012	(16)
Other Covered Loans [Member]
Changes in accretable yield of loans acquired with deteriorated credit quality
Balance at January 1, 2012	(9,757)
Reclasses from nonaccretable difference	(10,648)
Accretion	12,454
Balance at September 30, 2012	(7,951)
Not Covered Loans [Member]
Changes in accretable yield of loans acquired with deteriorated credit quality
Balance at January 1, 2012	(746)
Reclasses from nonaccretable difference	(1,702)
Accretion	1,280
Balance at September 30, 2012	$ (1,168)