Stock-Based Compensation - Absolute Share Price Compared Against Total Return Targets (Details) - Market-Based - Performance Shares	6 Months Ended
	Jun. 30, 2019	[1]
$40.00 and above
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout as a percentage of total return target	200.00%
$35.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout as a percentage of total return target	100.00%
$30.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout as a percentage of total return target	50.00%
Below $30.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout as a percentage of total return target	0.00%

[1] For performance between the levels described above, the degree of vesting is interpolated on a linear basis.