Pension and Other Post-Retirement Benefits Fair Value of Benefit Plan Assets (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Other Postretirement Benefit Plans, Defined Benefit [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 7,133	$ 6,465	$ 6,475
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	7,133	6,465
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	116	160
Other Postretirement Benefit Plans, Defined Benefit [Member] | Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fixed Income Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	2,379	2,234
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fixed Income Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fixed Income Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	4,638	4,071
Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Pension Plans, Defined Benefit [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	45,406	36,783	36,990
Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	45,406	36,783
Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Pension Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Pension Plans, Defined Benefit [Member] | Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	483	172
Pension Plans, Defined Benefit [Member] | Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Pension Plans, Defined Benefit [Member] | Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Pension Plans, Defined Benefit [Member] | Fixed Income Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	15,769	12,491
Pension Plans, Defined Benefit [Member] | Fixed Income Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Pension Plans, Defined Benefit [Member] | Fixed Income Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Pension Plans, Defined Benefit [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	29,154	24,120
Pension Plans, Defined Benefit [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Pension Plans, Defined Benefit [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value of Benefit Plan Assets [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 0	$ 0