Defined Benefit Pension Plans Multiemployer Pension Plans (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Multiemployer Plans [Line Items]
Multiemployer Plan, Period Contributions	$ 855	$ 492	$ 502
National Electric Benefit Fund [Member]
Multiemployer Plans [Line Items]
Number of collective-bargaining agreements	8
Multiemployer Plan, Period Contributions	755	417	442
Eighth District Electrical Pension Fund [Member]
Multiemployer Plans [Line Items]
Number of collective-bargaining agreements	1
Multiemployer Plan, Period Contributions	$ 100	$ 75	$ 60