Fair Value Measurement (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013 Level 3 Contingent acquisition consideration	Mar. 31, 2013 Level 3 Contingent acquisition consideration Minimum	Mar. 31, 2013 Level 3 Contingent acquisition consideration Maximum	Mar. 31, 2013 Recurring basis Total Fair Value	Dec. 31, 2012 Recurring basis Total Fair Value	Mar. 31, 2013 Recurring basis Total Fair Value Contingent acquisition consideration	Dec. 31, 2012 Recurring basis Total Fair Value Contingent acquisition consideration	Mar. 31, 2013 Recurring basis Level 2	Dec. 31, 2012 Recurring basis Level 2	Mar. 31, 2013 Recurring basis Level 3 Contingent acquisition consideration	Dec. 31, 2012 Recurring basis Level 3 Contingent acquisition consideration
Fair Value Inputs
Probability of contingent consideration (as a percent)		10.00%	95.00%
Weighted average discount rate (as a percent)	11.00%
Liabilities:
Interest Rate Swaps				$ (538)	$ (794)			$ (538)	$ (794)
Liabilities						$ (3,016)	$ (3,324)			$ (3,016)	$ (3,324)