Fair Value Measurements Investments (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Held-to-maturity Securities [Line Items]
Fair value of interest rate swap	$ 1,828	$ 2,866
Held-to-maturity Securities	22,399	22,510
Moody's, Aa2 Rating [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities	4,066	6,310
Moody's, A1 Rating [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities	18,333	16,200
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of Held-to-maturity Securities [Line Items]
Fair value of interest rate swap	1,828	2,866
Interest Rate Cash Flow Hedging Instrument Liability, Tax Effect	716	1,121
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net	$ (1,112)	$ (1,745)