Earnings Per Share - Common Shares Related to Stock Options and RSUs Excluded from Calculated Diluted EPS (Parenthetical) (Details) - shares	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	3,879,000	[1]	2,704,000	[2]	1,641,000	[3]
Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	3,019,000	[1]	2,142,000	[2]	1,450,000	[3]
Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	860,000	[1]	562,000	[2]	191,000	[3]
Performance Shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	137,799		79,465		110,666
Performance Shares | Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	125,000		66,666		66,666
Performance Shares | Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	12,799		12,799		44,000

[1] These totals do not include 125,000 performance based options and 12,799 performance based RSUs representing the right to acquire 137,799 shares of common stock for which all targets required to trigger vesting had not been achieved; therefore, such awards were excluded from the calculation of weighted average shares used to compute Diluted EPS for those reporting periods.

[2] These totals do not include 66,666 performance based options and 12,799 performance based RSUs representing the right to acquire 79,465 shares of common stock for which all targets required to trigger vesting had not been achieved; therefore, such awards were excluded from the calculation of weighted average shares used to compute Diluted EPS for those reporting periods.

[3] These totals do not include 66,666 performance based options and 44,000 performance based RSUs representing the right to acquire 110,666 shares of common stock, respectively, for which all targets required to trigger vesting had not been achieved; therefore, such awards were excluded from the calculation of weighted average shares used to compute Diluted EPS for those reporting periods.