Business Combinations HealthTran (Details) (USD $)
3 Months Ended 6 Months Ended
Jun. 30, 2013
Jun. 30, 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 $ 94,400,000 $ 94,400,000  
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 74,530,000  
Amortization of Acquired Intangible Assets 3,600,000 7,300,000  
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year 7,300,000 7,300,000  
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 1,750,000  
Estimated useful life   6 months  
Customer relationships | HealthTran
     
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]      
Customer relationships intangible 69,800,000 69,800,000  
Non-compete agreements | HealthTran
     
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]      
Customer relationships intangible 2,600,000 2,600,000  
Estimated useful life   5 years  
License | HealthTran
     
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]      
Customer relationships intangible $ 380,000 $ 380,000  
Estimated useful life   3 years  
Minimum | Customer relationships | HealthTran
     
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]      
Estimated useful life   4 years  
Maximum | Customer relationships | HealthTran
     
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]      
Estimated useful life   9 years  
[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.