Business Combinations (Details) 2 (USD $)
3 Months Ended
Mar. 31, 2013
Jan. 31, 2012
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]    
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year $ 144,100,000  
HealthTran
   
Business Acquisition [Line Items]    
Cash paid to shareholders   250,000,000
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]    
Customer relationships intangible 74,530,000  
Amortization of Acquired Intangible Assets 3,600,000  
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year 10,900,000  
Initial Amounts Recognized at Acquisition Date | HealthTran
   
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]    
Total current assets   30,654,000 [1]
Property and equipment   2,787,000 [1]
Goodwill   173,642,000 [1]
Customer relationships intangible   77,130,000 [1]
Total assets acquired   284,213,000 [1]
Current liabilities   36,784,000 [1]
Total liabilities assumed   36,784,000 [1]
Net assets acquired   247,429,000 [1]
Measurement Period Adjustments | HealthTran
   
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]    
Total current assets   245,000 [2]
Goodwill   833,000 [2]
Customer relationships intangible   (2,600,000) [2]
Total assets acquired   (1,522,000) [2]
Current liabilities   (496,000) [2]
Total liabilities assumed   (496,000) [2]
Net assets acquired   (1,026,000) [2]
Payments due to previous owners 1,000,000  
Current Amounts Recognized at Acquisition Date | HealthTran
   
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]    
Total current assets   30,899,000
Property and equipment   2,787,000
Goodwill   174,475,000
Customer relationships intangible   74,530,000
Total assets acquired   282,691,000
Current liabilities   36,288,000
Total liabilities assumed   36,288,000
Net assets acquired   246,403,000
Trademarks/Trade names | HealthTran
   
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]    
Customer relationships intangible 1,750,000  
Estimated useful life 6  
Customer relationships | HealthTran
   
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]    
Customer relationships intangible 69,800,000  
Non-compete agreements | HealthTran
   
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]    
Customer relationships intangible 2,600,000  
Estimated useful life 5  
License | HealthTran
   
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]    
Customer relationships intangible $ 380,000  
Estimated useful life 3  
Minimum | Customer relationships | HealthTran
   
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]    
Estimated useful life 4  
Maximum | Customer relationships | HealthTran
   
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]    
Estimated useful life 9  
[1] As previously reported in the Company's Form 10-Q for the period ended March 31, 2012.
[2] These represent measurement period adjustments from the acquisition date through December 31, 2012 and were recorded to reflect changes in the estimated fair values of the associated assets acquired and liabilities assumed based on factors existing as of the acquisition date.