XML 98 R122.htm IDEA: XBRL DOCUMENT v2.4.1.9
Segment Reporting (Narrative) (Details)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Segment Reporting [Abstract]      
Percentage threshold of company revenue not exceeded by any other country 17.60%cik0000914748_PercentageThresholdOfCompanyRevenueNotExceededByAnyOtherCountry 19.60%cik0000914748_PercentageThresholdOfCompanyRevenueNotExceededByAnyOtherCountry 20.30%cik0000914748_PercentageThresholdOfCompanyRevenueNotExceededByAnyOtherCountry