Employee Benefit Plans (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2016 USD ($) $ / shares shares	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) Plan $ / shares shares	Sep. 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	$ 89,000	$ 60,000	$ 269,000	$ 215,000
Directors [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Deferred compensation liability	934,000		934,000		$ 958,000
Deferred interest expense	3,000	5,000	11,000	17,000
Pension Plan [Member]
Components of net periodic benefit cost [Abstract]
Service cost	90,000	110,000	269,000	242,000
Interest cost	172,000	128,000	517,000	281,000
Expected return on plan assets	(260,000)	(243,000)	(780,000)	(533,000)
Net amortization and deferral	61,000	65,000	182,000	141,000
Net periodic benefit cost	63,000	60,000	188,000	131,000
Defined Benefit Plans Other Disclosure [Abstract]
Employer contribution to pension plan			818,000
Supplemental Executive Retirement Plans [Member]
Defined Benefit Plans Other Disclosure [Abstract]
Obligation included in other liabilities	1,430,000		1,430,000		1,339,000
Cost recognized	30,000	35,000	91,000	106,000
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	719,000		719,000		$ 710,000
Cost recognized	$ 17,000		$ 49,000
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	8,603		8,269
Granted (in shares) | shares	0		3,650
Forfeited (in shares) | shares	0		0
Vested (in shares) | shares	0		(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	$ 48.88		$ 49.98
Granted (in dollars per share) | $ / shares	0		47.81
Forfeited (in dollars per share) | $ / shares	0		0
Vested (in dollars per share) | $ / shares	0		50.45
Outstanding, end of period (in dollars per share) | $ / shares	$ 48.88		$ 48.88
Additional General Disclosures [Abstract]
Share-based compensation expense	$ 50,000	$ 44,000	$ 142,000	$ 129,000
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 6 months