Retirement Plan (Net Periodic Pension Expense) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive Income (Loss), Finalization of Pension and Non-Pension Postretirement Plan Valuation, before Tax	$ 1,726
Defined Benefit Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefit earned during the period	0	170
Interest cost on projected benefit obligations	899	991
Expected return on plan assets	(46)	(950)
Amortization of prior service cost	0	17
Amortization of net loss	693	483
Estimated effect of curtailment	0	225
Net periodic pension expense	1,546	936
Other Post-Retirement Healthcare and Other Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefit earned during the period	278	475
Interest cost on projected benefit obligations	159	875
Amortization of prior service cost	(1,474)	(550)
Amortization of net loss	31	75
Other Comprehensive Income (Loss), Finalization of Pension and Non-Pension Postretirement Plan Valuation, before Tax	1,726	0
Net periodic pension expense	$ 720	$ 875