Income Taxes (Tables)
 3 Months Ended
Mar. 31, 2015
Income Tax Disclosure [Abstract]  
Schedule of Effective Income Tax Rate Reconciliation
The following table provides a reconciliation of the federal income tax rate to the Company's effective income tax rate for the first quarters ended March 31, 2015 and 2014.
 
Quarter Ended
 
March 31
 
2015
 
2014
Federal income tax rate
35
 %
 
35
 %
Tax credits, net of equity adjustment
(4
)%
 
(4
)%
Permanent differences
(2
)%
 
(2
)%
Effective income tax rate
29
 %
 
29
 %