Defined Benefit Pension Plans Fair Value of Plan Assets (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Total Carrying Value at December 31, 2012	$ 22,957	$ 22,078
Fair value of plan assets	22,957	22,078	23,867
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	20,463	19,895
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,494	2,183
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Money market funds
Defined Benefit Plan Disclosure [Line Items]
Total Carrying Value at December 31, 2012	2,494	2,183
Money market funds | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Money market funds | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,494	2,183
Money market funds | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S. large-cap equities, growth [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Carrying Value at December 31, 2012	2,482	2,317
U.S. large-cap equities, growth [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,482	2,317
U.S. large-cap equities, growth [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S. large-cap equities, growth [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S. large-cap equities, value [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Carrying Value at December 31, 2012	1,767	2,136
U.S. large-cap equities, value [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,767	2,136
U.S. large-cap equities, value [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S. large-cap equities, value [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S. small/mid-cap equities, growth [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Carrying Value at December 31, 2012	1,516	1,816
U.S. small/mid-cap equities, growth [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,516	1,816
U.S. small/mid-cap equities, growth [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S. small/mid-cap equities, growth [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S. small/mid-cap equities, value [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Carrying Value at December 31, 2012	2,149	2,134
U.S. small/mid-cap equities, value [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,149	2,134
U.S. small/mid-cap equities, value [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S. small/mid-cap equities, value [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
International equities, growth [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Carrying Value at December 31, 2012	2,183	2,081
International equities, growth [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,183	2,081
International equities, growth [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
International equities, growth [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
International equities, value [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Carrying Value at December 31, 2012	2,083	2,017
International equities, value [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,083	2,017
International equities, value [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
International equities, value [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fixed income
Defined Benefit Plan Disclosure [Line Items]
Total Carrying Value at December 31, 2012	4,654	4,199
Fixed income | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,654	4,199
Fixed income | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fixed income | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Multiclass world-allocation mutual funds
Defined Benefit Plan Disclosure [Line Items]
Total Carrying Value at December 31, 2012	3,629	3,195
Multiclass world-allocation mutual funds | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,629	3,195
Multiclass world-allocation mutual funds | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Multiclass world-allocation mutual funds | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	$ 0