Employee Benefit Plans (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2016 USD ($) $ / shares shares	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) Plan $ / shares shares	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Employee Benefit Plans [Abstract]
Number of plans | Plan			2
Defined Contribution Plan [Abstract]
Employer contribution to 401 (k) defined contribution plan	$ 97,000	$ 93,000	$ 180,000	$ 155,000
Directors [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Deferred compensation liability	929,000		929,000		$ 958,000
Deferred interest expense	4,000	5,000	8,000	12,000
Pension Plan [Member]
Components of net periodic benefit cost [Abstract]
Service cost	89,000	78,000	179,000	132,000
Interest cost	173,000	90,000	345,000	153,000
Expected return on plan assets	(260,000)	(172,000)	(520,000)	(290,000)
Net amortization and deferral	60,000	45,000	121,000	76,000
Net periodic benefit cost	62,000	41,000	125,000	71,000
Defined Benefit Plans Other Disclosure [Abstract]
Employer contribution to pension plan			700,000
Supplemental Executive Retirement Plans [Member]
Defined Benefit Plans Other Disclosure [Abstract]
Obligation included in other liabilities	1,400,000		1,400,000		1,339,000
Cost recognized	31,000	36,000	61,000	71,000
Continuation of Life Insurance Plan [Member]
Defined Benefit Plans Other Disclosure [Abstract]
Obligation included in other liabilities	574,000		574,000		574,000
Salary Continuation Plan [Member]
Defined Benefit Plans Other Disclosure [Abstract]
Obligation included in other liabilities	716,000		716,000		$ 710,000
Cost recognized	$ 16,000		$ 32,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares) | shares	150,000		150,000
Number of shares available for grant (in shares) | shares	146,350		146,350
Restricted stock activity [Roll Forward]
Outstanding, beginning of period (in shares) | shares	8,111		8,269
Granted (in shares) | shares	3,650		3,650
Forfeited (in shares) | shares	0		0
Vested (in shares) | shares	(3,158)		(3,316)
Outstanding, end of period (in shares) | shares	8,603		8,603
Weighted average market price [Roll Forward]
Outstanding, beginning of period (in dollars per share) | $ / shares	$ 49.96		$ 49.98
Granted (in dollars per share) | $ / shares	47.81		47.81
Forfeited (in dollars per share) | $ / shares	0		0
Vested (in dollars per share) | $ / shares	50.41		(50.45)
Outstanding, end of period (in dollars per share) | $ / shares	$ 48.88		$ 48.88
Additional General Disclosures [Abstract]
Share-based compensation expense	$ 45,000	$ 43,000	$ 92,000	$ 85,000
Compensation cost related to nonvested awards that has not yet been recognized	$ 421,000		$ 421,000
Period over which compensation cost is expected to be recognized			2 years 9 months