Fair Value Measurements - Fair Value by Balance Sheet Grouping (Details) - USD ($)	Jun. 30, 2016	Dec. 31, 2015
Financial liabilities:
Borrowed funds	$ 138,850,000	$ 115,500,000
Additional Fair Value Information
Accrued interest receivable	1,530,000	1,414,000
Carrying Amount
Financial assets:
Loans, net	504,311,000	467,023,000
FHLB stock	6,500,000	5,283,000
Financial liabilities:
Certificates of deposit	114,636,000	109,038,000
Borrowed funds	138,850,000	115,500,000
Carrying Amount | Level 2
Additional Fair Value Information
Accrued interest payable	38,000	24,000
Carrying Amount | Level 3
Additional Fair Value Information
Accrued interest receivable	1,500,000	1,400,000
Fair Value
Financial assets:
Loans, net	513,306,000	471,245,000
Financial liabilities:
Certificates of deposit	114,885,000	109,423,000
Borrowed funds	138,845,000	115,495,000
Fair Value | Level 2
Financial liabilities:
Certificates of deposit	114,885,000	109,423,000
Borrowed funds	138,845,000	115,495,000
Fair Value | Level 3
Financial assets:
Loans, net	$ 513,306,000	$ 471,245,000