Employee Benefit Plans (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Components of net periodic benefit cost [Abstract]
Employer contribution to 401 (k) defined contribution plan	$ 57,000	$ 56,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized under restricted stock plan (in shares)	100,000
Number of restricted stock available for grant (in shares)	67,364
Restricted stock activity [Roll Forward]
Outstanding, beginning of period	7,172	8,646
Granted	392	0
Forfeited	0	(55)
Vested	(1,324)	(1,322)
Outstanding, end of period	6,240	7,269
Weighted average market price [Roll Forward]
Outstanding, beginning of period (in dollars per share)	$ 42.02	$ 35.51
Granted (in dollars per share)	$ 50.50	$ 0
Forfeited (in dollars per share)	$ 0	$ 37.10
Vested (in dollars per share)	$ 37.35	$ 37.35
Outstanding, end of period (in dollars per share)	$ 43.55	$ 35.16
Share-based compensation expense	36,000	38,000
Directors [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Deferred interest expense	5,000	4,000
Pension Plan [Member]
Components of net periodic benefit cost [Abstract]
Service cost	90,000	101,000
Interest cost	96,000	106,000
Expected return on plan assets	(122,000)	(174,000)
Net amortization and deferral	12,000	42,000
Net periodic benefit cost	76,000	75,000
Employer contribution to pension plan	500,000
Supplemental Executive Retirement Plans [Member]
Components of net periodic benefit cost [Abstract]
Obligation included in other liabilities	1,084,000		1,046,000
Cost recognized	38,000	36,000
Deferred Compensation Plan [Member]
Components of net periodic benefit cost [Abstract]
Obligation included in other liabilities	$ 949,000		$ 981,000