Fair Value Measurements - Fair Value by Balance Sheet Grouping (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Financial assets:
Available-for-sale investment securities	$ 447,016,000	$ 443,224,000
Carrying Value
Financial assets:
Cash and due from banks	28,059,000	25,878,000
Interest-earning deposits in other banks	26,658,000	85,956,000
Federal funds sold	331,000	218,000
Available-for-sale investment securities	447,016,000	443,224,000
Held-to-maturity investment securities	31,837,000
Loans, net	547,247,000	503,149,000
Federal Home Loan Bank stock	4,791,000	4,499,000
Accrued interest receivable	5,223,000	5,026,000
Financial liabilities:
Deposits	1,008,863,000	1,004,143,000
Junior subordinated deferrable interest debentures	5,155,000	5,155,000
Accrued interest payable	110,000	129,000
Level 1
Financial assets:
Cash and due from banks	28,059,000	25,878,000
Interest-earning deposits in other banks	26,658,000	85,956,000
Federal funds sold	331,000	218,000
Available-for-sale investment securities	7,529,000	7,514,000
Held-to-maturity investment securities	0
Loans, net	0	0
Accrued interest receivable	22,000	21,000
Financial liabilities:
Deposits	847,644,000	834,864,000
Junior subordinated deferrable interest debentures	0	0
Accrued interest payable	0	0
Level 2
Financial assets:
Cash and due from banks	0	0
Interest-earning deposits in other banks	0	0
Federal funds sold	0	0
Available-for-sale investment securities	439,487,000	435,710,000
Held-to-maturity investment securities	34,523,000
Loans, net	0	0
Accrued interest receivable	2,819,000	2,976,000
Financial liabilities:
Deposits	161,213,000	169,065,000
Junior subordinated deferrable interest debentures	0	0
Accrued interest payable	86,000	105,000
Level 3
Financial assets:
Cash and due from banks	0	0
Interest-earning deposits in other banks	0	0
Federal funds sold	0	0
Available-for-sale investment securities	0	0
Held-to-maturity investment securities	0
Loans, net	550,002,000	507,361,000
Accrued interest receivable	2,382,000	2,029,000
Financial liabilities:
Deposits	0	0
Junior subordinated deferrable interest debentures	3,175,000	2,750,000
Accrued interest payable	24,000	24,000
Fair Value
Financial assets:
Cash and due from banks	28,059,000	25,878,000
Interest-earning deposits in other banks	26,658,000	85,956,000
Federal funds sold	331,000	218,000
Available-for-sale investment securities	447,016,000	443,224,000
Held-to-maturity investment securities	34,523,000
Loans, net	550,002,000	507,361,000
Accrued interest receivable	5,223,000	5,026,000
Financial liabilities:
Deposits	1,008,857,000	1,003,929,000
Junior subordinated deferrable interest debentures	3,175,000	2,750,000
Accrued interest payable	$ 110,000	$ 129,000