Retirement Plans - Change in Benefit Obligations and Plan Assets (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension plan
Change in benefit obligation - Pension
Benefit obligation at beginning of year	$ 9,326		$ 10,215
Service cost	248	359	284
Interest cost	392	402	375
Actuarial gain/assumption changes	2,804	(1,379)
Benefits paid	(1,719)	(271)
Benefit obligation at end of year	11,051	9,326
Accumulated benefit obligation at end of year	9,473	8,427
Change in Plan Assets
Fair value of plan assets at beginning of year	8,633		6,799
Actual return on plan assets	407	1,105
Employer contribution	650	1,000
Benefits/expenses paid	(1,718)	(271)
Fair value of plan assets at end of year	7,972	8,633
Funded status - liability	(3,079)	(693)
Amounts recorded in stockholders’ equity
Net actuarial (gain) loss	4,453	1,961
Prior service cost	(119)	(148)
Total amount recorded	4,334	1,813
Amount recorded, net taxes	2,600	1,088
SERP
Change in benefit obligation - Pension
Benefit obligation at beginning of year	6,131		6,507
Service cost	26	318	525
Interest cost	258	219	208
Actuarial gain/assumption changes	1,399	(913)
Benefits paid	(383)	0
Benefit obligation at end of year	7,431	6,131
Accumulated benefit obligation at end of year	6,937	6,099
Change in Plan Assets
Funded status - liability	(7,431)	(6,131)
Amounts recorded in stockholders’ equity
Net actuarial (gain) loss	2,072	696
Prior service cost	0	0
Total amount recorded	2,072	696
Amount recorded, net taxes	$ 1,243	$ 418