Commitments and Contingencies (Outstanding Commitments to Extend Credit) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Long-term Purchase Commitment [Line Items]
Unused commitments to extend credit	$ 491,132	$ 234,777
One-to-four Family Residential
Long-term Purchase Commitment [Line Items]
Unused commitments to extend credit	0	45
Commercial Business
Long-term Purchase Commitment [Line Items]
Unused commitments to extend credit	311,818	174,296
Commercial Business | Commercial and Industrial
Long-term Purchase Commitment [Line Items]
Unused commitments to extend credit	288,930	169,079
Commercial Business | Owner-occupied Commercial Real Estate
Long-term Purchase Commitment [Line Items]
Unused commitments to extend credit	2,648	2,812
Commercial Business | Non-owner Occupied Commercial Real Estate
Long-term Purchase Commitment [Line Items]
Unused commitments to extend credit	20,240	2,405
Real Estate Construction and Land Development
Long-term Purchase Commitment [Line Items]
Unused commitments to extend credit	56,681	32,956
Real Estate Construction and Land Development | One-to-four Family Residential
Long-term Purchase Commitment [Line Items]
Unused commitments to extend credit	24,028	12,236
Real Estate Construction and Land Development | Five or More Family Residential and Commercial Properties
Long-term Purchase Commitment [Line Items]
Unused commitments to extend credit	32,653	20,720
Consumer
Long-term Purchase Commitment [Line Items]
Unused commitments to extend credit	$ 122,633	$ 27,480