Fair Values of Assets and Liabilities (Measured on Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	$ 367,842	$ 350,040	[1]
US Government-sponsored Enterprises Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	2,036	2,044
Residential mortgage-backed securities - GSE [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	285,719	290,145
Residential mortgage-backed securities - Private [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	16,430	17,271
Commercial mortgage-backed securities - GSE [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	22,208	21,958
Commercial mortgage-backed securities - Private [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	10,457	10,215
Corporate notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	30,992	8,407
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	0	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	367,842	350,040
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	0	0
Recurring [Member] | Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	367,842	350,040
Mortgage servicing rights	1,896	1,726
Total assets at fair value	368,693	351,241
Recurring [Member] | Total [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	2,036	2,044
Recurring [Member] | Total [Member] | Residential mortgage-backed securities - GSE [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	285,719	290,145
Recurring [Member] | Total [Member] | Residential mortgage-backed securities - Private [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	16,430	17,271
Recurring [Member] | Total [Member] | Commercial mortgage-backed securities - GSE [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	22,208	21,958
Recurring [Member] | Total [Member] | Commercial mortgage-backed securities - Private [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	10,457	10,215
Recurring [Member] | Total [Member] | Corporate notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	30,992	8,407
Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	0	0
Mortgage servicing rights	0	0
Total assets at fair value	0	0
Recurring [Member] | Level 1 [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	0	0
Recurring [Member] | Level 1 [Member] | Residential mortgage-backed securities - GSE [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	0	0
Recurring [Member] | Level 1 [Member] | Residential mortgage-backed securities - Private [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	0	0
Recurring [Member] | Level 1 [Member] | Commercial mortgage-backed securities - GSE [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities		0
Recurring [Member] | Level 1 [Member] | Commercial mortgage-backed securities - Private [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	0	0
Recurring [Member] | Level 1 [Member] | Corporate notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	0	0
Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	367,842	350,040
Mortgage servicing rights	0	0
Total assets at fair value	366,797	349,515
Recurring [Member] | Level 2 [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	2,036	2,044
Recurring [Member] | Level 2 [Member] | Residential mortgage-backed securities - GSE [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	285,719	290,145
Recurring [Member] | Level 2 [Member] | Residential mortgage-backed securities - Private [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	16,430	17,271
Recurring [Member] | Level 2 [Member] | Commercial mortgage-backed securities - GSE [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	22,208	21,958
Recurring [Member] | Level 2 [Member] | Commercial mortgage-backed securities - Private [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	10,457	10,215
Recurring [Member] | Level 2 [Member] | Corporate notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	30,992	8,407
Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	0	0
Mortgage servicing rights	1,896	1,726
Total assets at fair value	1,896	1,726
Recurring [Member] | Level 3 [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	0	0
Recurring [Member] | Level 3 [Member] | Residential mortgage-backed securities - GSE [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	0	0
Recurring [Member] | Level 3 [Member] | Residential mortgage-backed securities - Private [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	0	0
Recurring [Member] | Level 3 [Member] | Commercial mortgage-backed securities - GSE [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities		0
Recurring [Member] | Level 3 [Member] | Commercial mortgage-backed securities - Private [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	0	0
Recurring [Member] | Level 3 [Member] | Corporate notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale investment securities	0	0
Interest Rate Swap [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative assets	0
Interest Rate Swap [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative assets	(1,044)
Interest Rate Swap [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative assets	0
Interest Rate Swap [Member] | Recurring [Member] | Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative assets	(1,045)	(525)
Interest Rate Swap [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative assets	0	0
Interest Rate Swap [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative assets	(1,045)	(525)
Interest Rate Swap [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative assets	$ 0	$ 0

[1] Derived from audited consolidated financial statements