Fair Value Measurement - Assets Recorded at Fair Value and Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount for selling costs	10.00%
Fair Value	$ 285,485	$ 285,485	$ 276,984
Recurring | Level 1
Available-for-sale securities:
Obligations of state and political subdivisions	0	0	0
GSE mortgage-backed securities	0	0	0
Collateralized mortgage obligations: residential	0	0	0
Collateralized mortgage obligations: commercial	0	0	0
Mutual funds	2,116	2,116	2,104
U.S. Government sponsored enterprises			0
Other asset-backed securities			0
Collateralized debt obligation			0
Recurring | Level 2
Available-for-sale securities:
Obligations of state and political subdivisions	37,431	37,431	44,605
GSE mortgage-backed securities	91,739	91,739	109,103
Collateralized mortgage obligations: residential	148,582	148,582	60,839
Collateralized mortgage obligations: commercial	5,617	5,617	24,545
Mutual funds	0	0	0
U.S. Government sponsored enterprises			10,227
Other asset-backed securities			24,343
Collateralized debt obligation			1,218
Recurring | Level 3
Available-for-sale securities:
Obligations of state and political subdivisions	0	0	0
GSE mortgage-backed securities	0	0	0
Collateralized mortgage obligations: residential	0	0	0
Collateralized mortgage obligations: commercial	0	0	0
Mutual funds	0	0	0
U.S. Government sponsored enterprises			0
Other asset-backed securities			0
Collateralized debt obligation			0
Nonrecurring
Assets and Liabilities Measured on Nonrecurring Basis
Impaired loans	14,966	14,966	5,051
Other real estate	4,661	4,661	4,234
Nonrecurring | Level 1
Assets and Liabilities Measured on Nonrecurring Basis
Impaired loans	0	0	0
Other real estate	0	0	0
Nonrecurring | Level 2
Assets and Liabilities Measured on Nonrecurring Basis
Impaired loans	14,966	14,966	5,051
Other real estate	4,661	4,661	4,234
Nonrecurring | Level 3
Assets and Liabilities Measured on Nonrecurring Basis
Impaired loans	0	0	0
Other real estate	0	0	0
Obligations of state and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	37,431	37,431	44,605
Obligations of state and political subdivisions | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	37,431	37,431	44,605
GSE mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	91,739	91,739	109,103
GSE mortgage-backed securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	91,739	91,739	109,103
Collateralized mortgage obligations: residential
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	148,582	148,582	60,839
Collateralized mortgage obligations: residential | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	148,582	148,582	60,839
Collateralized mortgage obligations: commercial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	5,617	5,617	24,545
Collateralized mortgage obligations: commercial | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	5,617	5,617	24,545
Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	2,116	2,116	2,104
Mutual funds | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 2,116	$ 2,116	2,104
U.S. Government sponsored enterprises
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value			10,227
U.S. Government sponsored enterprises | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value			10,227
Other asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value			24,343
Other asset-backed securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value			24,343
Collateralized debt obligation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value			1,218
Collateralized debt obligation | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value			$ 1,218
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Period when new appraisals are received		28 days
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Period when new appraisals are received		42 days