Goodwill and Other Intangible Assets (Tables)
 3 Months Ended
Mar. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]  
Changes in carrying amounts of goodwill by reportable segments
The changes in the carrying amounts of goodwill by reportable segment for the three months ended March 31, 2015 are as follows (in thousands):
 
PBM
 
HCIT
 
Total
Balance at December 31, 2014
$
4,704,974

 
$
19,665

 
$
4,724,639

Acquisition (a)
199,026

 
—

 
199,026

Balance at March 31, 2015
$
4,904,000

 
$
19,665

 
$
4,923,665



(a)
Initial goodwill recorded in connection with the acquisition of Salveo in January 2015.
Components of intangible assets
Definite-lived intangible assets are amortized over the useful lives of the related assets. The components of intangible assets were as follows (in thousands):
 
March 31, 2015
 
December 31, 2014
 
Gross Carrying Amount
 
 Accumulated Amortization
 
Net
 
Gross Carrying Amount
 
 Accumulated Amortization
 
Net
Customer relationships
$
1,552,022

 
$
603,064

 
$
948,958

 
$
1,527,722

 
$
564,623

 
$
963,099

Non-compete agreements
11,920

 
7,044

 
4,876

 
11,920

 
7,435

 
4,485

Other intangible assets
28,100

 
1,454

 
26,646

 
3,060

 
2,445

 
615

Total
$
1,592,042

 
$
611,562

 
$
980,480

 
$
1,542,702

 
$
574,503

 
$
968,199