Fair Value Measurements (Fair Value Measurement on Nonrecurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Fair value measurements of assets on a nonrecurring basis
Investment securities held to maturity, Total	$ 36,874		$ 36,340
Other real estate owned, Basis	3,355		4,559		5,666	4,484
Level 1
Fair value measurements of assets on a nonrecurring basis
Investment securities held to maturity, Total	0		0
Level 2
Fair value measurements of assets on a nonrecurring basis
Investment securities held to maturity, Total	36,874		36,340
Level 3
Fair value measurements of assets on a nonrecurring basis
Investment securities held to maturity, Total	0		0
Nonrecurring
Fair value measurements of assets on a nonrecurring basis
Total, Basis	2,340	[1]	18,382	[1]
Total	1,919		13,185
Total, Net Losses (Gains) Recorded in Earnings	423		1,229
Nonrecurring | Level 1
Fair value measurements of assets on a nonrecurring basis
Total	0		0
Nonrecurring | Level 2
Fair value measurements of assets on a nonrecurring basis
Total	11		19
Nonrecurring | Level 3
Fair value measurements of assets on a nonrecurring basis
Total	1,908		13,166
Nonrecurring | Private Residential Collateralized Mortgage Obligations
Fair value measurements of assets on a nonrecurring basis
Investment securities held to maturity, Basis	36	[1]	19	[1]
Investment securities held to maturity, Total	11		19
Total, Net Losses (Gains) Recorded in Earnings	45		38
Nonrecurring | Private Residential Collateralized Mortgage Obligations | Level 1
Fair value measurements of assets on a nonrecurring basis
Investment securities held to maturity, Total	0		0
Nonrecurring | Private Residential Collateralized Mortgage Obligations | Level 2
Fair value measurements of assets on a nonrecurring basis
Investment securities held to maturity, Total	11		19
Nonrecurring | Private Residential Collateralized Mortgage Obligations | Level 3
Fair value measurements of assets on a nonrecurring basis
Investment securities held to maturity, Total	0		0
Nonrecurring | Commercial Properties
Fair value measurements of assets on a nonrecurring basis
Other real estate owned, Basis			1,720	[1]
Other real estate owned, Total			1,222
Total, Net Losses (Gains) Recorded in Earnings			348
Nonrecurring | Commercial Properties | Level 1
Fair value measurements of assets on a nonrecurring basis
Other real estate owned, Total			0
Nonrecurring | Commercial Properties | Level 2
Fair value measurements of assets on a nonrecurring basis
Other real estate owned, Total			0
Nonrecurring | Commercial Properties | Level 3
Fair value measurements of assets on a nonrecurring basis
Other real estate owned, Total			1,222
Nonrecurring | Noncovered Impaired Loans
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Basis	2,304	[1]	12,442	[1]
Impaired originated loans, Total			8,403
Total, Net Losses (Gains) Recorded in Earnings	378		230
Nonrecurring | Noncovered Impaired Loans | Level 1
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total	0		0
Nonrecurring | Noncovered Impaired Loans | Level 2
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total	0		0
Nonrecurring | Noncovered Impaired Loans | Level 3
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total	1,908		8,403
Nonrecurring | Noncovered Impaired Loans | One-to-four Family Residential
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Basis			0	[1]
Impaired originated loans, Total			0
Total, Net Losses (Gains) Recorded in Earnings			0
Nonrecurring | Noncovered Impaired Loans | One-to-four Family Residential | Level 1
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Noncovered Impaired Loans | One-to-four Family Residential | Level 2
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Noncovered Impaired Loans | One-to-four Family Residential | Level 3
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Noncovered Impaired Loans | Commercial Business
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Basis	161	[1]	10,853	[1]
Impaired originated loans, Total	138		7,178
Total, Net Losses (Gains) Recorded in Earnings	23		(134)
Nonrecurring | Noncovered Impaired Loans | Commercial Business | Level 1
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total	0		0
Nonrecurring | Noncovered Impaired Loans | Commercial Business | Level 2
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total	0		0
Nonrecurring | Noncovered Impaired Loans | Commercial Business | Level 3
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total	138		7,178
Nonrecurring | Noncovered Impaired Loans | Commercial Business | Commercial and Industrial
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Basis	161	[1]	4,850	[1]
Impaired originated loans, Total	138		2,134
Total, Net Losses (Gains) Recorded in Earnings	23		1,681
Nonrecurring | Noncovered Impaired Loans | Commercial Business | Commercial and Industrial | Level 1
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total	0		0
Nonrecurring | Noncovered Impaired Loans | Commercial Business | Commercial and Industrial | Level 2
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total	0		0
Nonrecurring | Noncovered Impaired Loans | Commercial Business | Commercial and Industrial | Level 3
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total	138		2,134
Nonrecurring | Noncovered Impaired Loans | Commercial Business | Owner-occupied Commercial Real Estate
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Basis			1,880	[1]
Impaired originated loans, Total			1,285
Total, Net Losses (Gains) Recorded in Earnings			594
Nonrecurring | Noncovered Impaired Loans | Commercial Business | Owner-occupied Commercial Real Estate | Level 1
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Noncovered Impaired Loans | Commercial Business | Owner-occupied Commercial Real Estate | Level 2
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Noncovered Impaired Loans | Commercial Business | Owner-occupied Commercial Real Estate | Level 3
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			1,285
Nonrecurring | Noncovered Impaired Loans | Commercial Business | Non-owner Occupied Commercial Real Estate
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Basis			4,123	[1]
Impaired originated loans, Total			3,759
Total, Net Losses (Gains) Recorded in Earnings			(2,409)
Nonrecurring | Noncovered Impaired Loans | Commercial Business | Non-owner Occupied Commercial Real Estate | Level 1
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Noncovered Impaired Loans | Commercial Business | Non-owner Occupied Commercial Real Estate | Level 2
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Noncovered Impaired Loans | Commercial Business | Non-owner Occupied Commercial Real Estate | Level 3
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			3,759
Nonrecurring | Noncovered Impaired Loans | Real Estate Construction and Land Development
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Basis	2,094	[1]	911	[1]
Impaired originated loans, Total	1,725		700
Total, Net Losses (Gains) Recorded in Earnings	350		211
Nonrecurring | Noncovered Impaired Loans | Real Estate Construction and Land Development | Level 1
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total	0		0
Nonrecurring | Noncovered Impaired Loans | Real Estate Construction and Land Development | Level 2
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total	0		0
Nonrecurring | Noncovered Impaired Loans | Real Estate Construction and Land Development | Level 3
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total	1,725		700
Nonrecurring | Noncovered Impaired Loans | Real Estate Construction and Land Development | One-to-four Family Residential
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Basis	2,094	[1]	911	[1]
Impaired originated loans, Total	1,725		700
Total, Net Losses (Gains) Recorded in Earnings	350		211
Nonrecurring | Noncovered Impaired Loans | Real Estate Construction and Land Development | One-to-four Family Residential | Level 1
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total	0		0
Nonrecurring | Noncovered Impaired Loans | Real Estate Construction and Land Development | One-to-four Family Residential | Level 2
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total	0		0
Nonrecurring | Noncovered Impaired Loans | Real Estate Construction and Land Development | One-to-four Family Residential | Level 3
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total	1,725		700
Nonrecurring | Noncovered Impaired Loans | Consumer
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Basis	49	[1]	678	[1]
Impaired originated loans, Total	45		525
Total, Net Losses (Gains) Recorded in Earnings	5		153
Nonrecurring | Noncovered Impaired Loans | Consumer | Level 1
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total	0		0
Nonrecurring | Noncovered Impaired Loans | Consumer | Level 2
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total	0		0
Nonrecurring | Noncovered Impaired Loans | Consumer | Level 3
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total	45		525
Nonrecurring | Covered Impaired Loans
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Basis			4,201	[1]
Impaired originated loans, Total			3,541
Total, Net Losses (Gains) Recorded in Earnings			613
Nonrecurring | Covered Impaired Loans | Level 1
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Covered Impaired Loans | Level 2
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Covered Impaired Loans | Level 3
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			3,541
Nonrecurring | Covered Impaired Loans | One-to-four Family Residential
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Basis			450	[1]
Impaired originated loans, Total			419
Total, Net Losses (Gains) Recorded in Earnings			(13)
Nonrecurring | Covered Impaired Loans | One-to-four Family Residential | Level 1
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Covered Impaired Loans | One-to-four Family Residential | Level 2
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Covered Impaired Loans | One-to-four Family Residential | Level 3
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			419
Nonrecurring | Covered Impaired Loans | Commercial Business
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Basis			3,751	[1]
Impaired originated loans, Total			3,122
Total, Net Losses (Gains) Recorded in Earnings			628
Nonrecurring | Covered Impaired Loans | Commercial Business | Level 1
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Covered Impaired Loans | Commercial Business | Level 2
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Covered Impaired Loans | Commercial Business | Level 3
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			3,122
Nonrecurring | Covered Impaired Loans | Commercial Business | Commercial and Industrial
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Basis			3,751	[1]
Impaired originated loans, Total			3,122
Total, Net Losses (Gains) Recorded in Earnings			628
Nonrecurring | Covered Impaired Loans | Commercial Business | Commercial and Industrial | Level 1
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Covered Impaired Loans | Commercial Business | Commercial and Industrial | Level 2
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Covered Impaired Loans | Commercial Business | Commercial and Industrial | Level 3
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			3,122
Nonrecurring | Covered Impaired Loans | Commercial Business | Non-owner Occupied Commercial Real Estate
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Basis			0	[1]
Impaired originated loans, Total			0
Total, Net Losses (Gains) Recorded in Earnings			0
Nonrecurring | Covered Impaired Loans | Commercial Business | Non-owner Occupied Commercial Real Estate | Level 1
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Covered Impaired Loans | Commercial Business | Non-owner Occupied Commercial Real Estate | Level 2
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Covered Impaired Loans | Commercial Business | Non-owner Occupied Commercial Real Estate | Level 3
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Covered Impaired Loans | Consumer
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Basis			0	[1]
Impaired originated loans, Total			0
Total, Net Losses (Gains) Recorded in Earnings			(2)
Nonrecurring | Covered Impaired Loans | Consumer | Level 1
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Covered Impaired Loans | Consumer | Level 2
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			0
Nonrecurring | Covered Impaired Loans | Consumer | Level 3
Fair value measurements of assets on a nonrecurring basis
Impaired originated loans, Total			$ 0

[1] asis represents the unpaid principal balance of noncovered impaired and covered impaired loans, amortized cost of investment securities held to maturity, and carrying value at ownership date of other real estate owned.