Goodwill, Core Deposit Intangibles and Other Intangible Assets (Carrying Amount of Intangible Assets) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 35,737	$ 27,913
Accumulated Amortization	17,251	14,953
Net Carrying Amount	18,486	12,960
Core Deposit Intangibles
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	11,668	9,957
Accumulated Amortization	9,327	8,815
Net Carrying Amount	2,341	1,142
Mortgage Servicing Rights
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	22,892	16,779
Accumulated Amortization	7,239	5,503
Net Carrying Amount	15,653	11,276
Customer Relationship Intangible
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,177	1,177
Accumulated Amortization	685	635
Net Carrying Amount	$ 492	$ 542