Pension and Other Postretirement Plans (Components of Net Periodic Benefit Costs) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Pension Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost	$ 928	$ 1,000	$ 1,034
Service cost	174	147	0
Expected return on plan assets	(1,070)	(1,094)	(1,035)
Amortization of prior service cost	4	4	4
Amortization of net loss (gain)	786	542	499
Net periodic benefit cost	822	599	502
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Net (gain) loss	1,389	3,240
Amortization of prior service cost	(4)	(4)	(4)
Amortization of net loss (gain)	786	542	499
Total recognized in other comprehensive income	599	2,694
Total recognized in net periodic benefit cost and other comprehensive income	1,421	3,293
Chairman and President Non-Qualified Defined Benefit Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost	912	1,033	1,063
Service cost	168	93	53
Amortization of prior service cost	59	59	516
Amortization of net loss (gain)	1,142	888	658
Net periodic benefit cost	2,281	2,073	2,290
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Net (gain) loss	2,025	3,000
Amortization of prior service cost	(59)	(59)	(516)
Amortization of net loss (gain)	1,142	888	658
Total recognized in other comprehensive income	824	2,053
Total recognized in net periodic benefit cost and other comprehensive income	3,105	4,126
Defined Benefit Postretirement Healthcare Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost	129	143	137
Amortization of prior service cost	103	103	103
Amortization of net loss (gain)	41	19	0
Net periodic benefit cost	273	265	240
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Net (gain) loss	(105)	632
Amortization of prior service cost	(103)	(103)	(103)
Amortization of net loss (gain)	41	19	0
Total recognized in other comprehensive income	(249)	510
Total recognized in net periodic benefit cost and other comprehensive income	$ 24	$ 775