Fair Value Measurement (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 Level 3 Contingent acquisition consideration	Dec. 31, 2013 Level 3 Contingent acquisition consideration Minimum	Dec. 31, 2013 Level 3 Contingent acquisition consideration Maximum	Dec. 31, 2013 Recurring basis Level 2 Prepaid expenses and other	Dec. 31, 2012 Recurring basis Level 2 Other long term liabilities	Dec. 31, 2013 Recurring basis Level 3 Contingent acquisition consideration Accrued expenses	Dec. 31, 2012 Recurring basis Level 3 Contingent acquisition consideration Accrued expenses	Dec. 31, 2013 Recurring basis Level 3 Contingent acquisition consideration Other long term liabilities	Dec. 31, 2012 Recurring basis Level 3 Contingent acquisition consideration Other long term liabilities
Assets:
Interest Rate Swaps				$ 824
Liabilities:
Interest Rate Swaps					794
Contingent acquisition consideration						$ 1,374	$ 1,316	$ 163	$ 2,008
Fair Value Inputs
Probability of contingent consideration (as a percent)		20.00%	50.00%
Weighted average discount rate (as a percent)	7.00%