Annual report pursuant to Section 13 and 15(d)

Other Information - Net Income Attributable to Common Stockholders (Details)

v2.4.1.9
Other Information - Net Income Attributable to Common Stockholders (Details)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Basic weighted average shares outstanding 105,500,000us-gaap_WeightedAverageNumberOfSharesOutstandingBasic 115,900,000us-gaap_WeightedAverageNumberOfSharesOutstandingBasic 120,000,000us-gaap_WeightedAverageNumberOfSharesOutstandingBasic
Diluted weighted average shares outstanding 111,500,000us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding 121,100,000us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding 120,100,000us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount 1,400,000us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount 0us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount 2,900,000us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Employee Stock Option      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Effect of dilution: 5,300,000us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
3,800,000us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
0us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
Restricted Stock      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Effect of dilution: 700,000us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
1,400,000us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
100,000us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember