Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012
Summary of intangible assets
Gross Carrying Amount	$ 21,388
Accumulated Amortization	(8,758)
Net Carrying Amount	12,630
Core deposit intangibles [Member]
Summary of intangible assets
Gross Carrying Amount	14,800
Accumulated Amortization	(6,772)
Net Carrying Amount	8,028
Customer relationship intangibles [Member]
Summary of intangible assets
Gross Carrying Amount	5,657
Accumulated Amortization	(1,899)
Net Carrying Amount	3,758
Mortgage Servicing Intangibles [Member]
Summary of intangible assets
Gross Carrying Amount	931
Accumulated Amortization	(87)
Net Carrying Amount	$ 844