Retirement Plans - Change in Benefit Obligations and Plan Assets (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Pension plan [Member]
Change in benefit obligation
Benefit obligation at beginning of year	$ 8,701	$ 7,110
Service cost	284	251	239
Interest cost	(375)	(384)	(316)
Actuarial gain/assumption changes	1,344	1,591
Benefits paid	(489)	(635)
Benefit obligation at end of year	10,215	8,701	7,110
Accumulated benefit obligation at end of year	9,195	7,659
Change in Plan Assets
Fair value of plan assets at beginning of year	5,722	5,591
Actual return on plan assets	706	26
Employer contribution	860	791
Benefits/expenses paid	(489)	(686)
Fair value of plan assets at end of year	6,799	5,722	5,591
Funded status - liability	(3,416)	(2,979)
Amounts recorded in stockholders’ equity
Net actuarial (gain) loss	(4,110)	(3,236)
Prior service cost	176	205
Total amount recorded	(3,934)	(3,031)
Amount recorded, net taxes	(2,360)	(1,819)
SERP [Member]
Change in benefit obligation
Benefit obligation at beginning of year	5,474	3,196
Service cost	525	(172)	(223)
Interest cost	(208)	215	226
Actuarial gain/assumption changes	300	1,891
Benefit obligation at end of year	6,507	5,474	3,196
Accumulated benefit obligation at end of year	6,339	5,317
Change in Plan Assets
Funded status - liability	(6,507)	(5,474)
Amounts recorded in stockholders’ equity
Net actuarial (gain) loss	1,671	1,825
Prior service cost	0	0
Total amount recorded	1,671	1,825
Amount recorded, net taxes	$ 1,003	$ 1,098