Covered Loans Receivable (Covered Purchased Credit Impaired Loans) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Impaired [Line Items]
Recorded investment balance which are no longer covered under the FDIC shared-loss agreements	$ 476	$ 1,700
Covered Loans
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	57,362	38,876
Covered Loans | Outstanding Principal
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	62,338	40,043
Covered Loans | One-to-four Family Residential
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	3,478	3,530
Covered Loans | One-to-four Family Residential | Outstanding Principal
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	3,837	3,966
Covered Loans | Commercial Business
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	48,057	31,790
Covered Loans | Commercial Business | Outstanding Principal
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	53,313	32,757
Covered Loans | Commercial Business | Commercial and Industrial
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	7,134	8,680
Covered Loans | Commercial Business | Commercial and Industrial | Outstanding Principal
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	9,635	10,608
Covered Loans | Commercial Business | Owner-occupied Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	20,666	10,923
Covered Loans | Commercial Business | Owner-occupied Commercial Real Estate | Outstanding Principal
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	23,071	11,538
Covered Loans | Commercial Business | Non-owner Occupied Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	20,257	12,187
Covered Loans | Commercial Business | Non-owner Occupied Commercial Real Estate | Outstanding Principal
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	20,607	10,611
Covered Loans | Real Estate Construction and Land Development
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	3,110	1,556
Covered Loans | Real Estate Construction and Land Development | Outstanding Principal
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	2,243	1,298
Covered Loans | Real Estate Construction and Land Development | One-to-four Family Residential
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	1,308	1,556
Covered Loans | Real Estate Construction and Land Development | One-to-four Family Residential | Outstanding Principal
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	103	1,298
Covered Loans | Real Estate Construction and Land Development | Five or More Family Residential and Commercial Properties
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	1,802	0
Covered Loans | Real Estate Construction and Land Development | Five or More Family Residential and Commercial Properties | Outstanding Principal
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	2,140	0
Covered Loans | Consumer
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	2,717	2,000
Covered Loans | Consumer | Outstanding Principal
Financing Receivable, Impaired [Line Items]
Recorded investment of PCI loans	$ 2,945	$ 2,022