Earnings Per Share - Common Shares Related to Stock Options and RSUs Excluded from Calculated Diluted EPS (Details) - shares shares in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	[1]	3,758	2,981
Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	[1]	2,871	2,141
Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	[1]	887	840

[1] These totals do not include 12,799 performance based RSUs and 66,666 performance based options for the three months ended March 31, 2016 and 2015, respectively, representing the right to acquire the equivalent number of shares of common stock for which all targets required to trigger vesting have not been achieved; therefore, such awards were excluded from the calculation of weighted average shares used to compute Diluted EPS for those reporting periods.