Stock-Based Compensation - Schedule of Grants (Details) - shares	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding (in shares)	264,246	264,246
RSUs Outstanding (in shares)	1,071,538
Options and RSUs Exercised (in shares)	3,730,825
Available Shares (in shares)	2,479,242
Total (in shares)	7,545,851
2017 ECP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding (in shares)	0
RSUs Outstanding (in shares)	125,000
Options and RSUs Exercised (in shares)	0
Available Shares (in shares)	1,875,000
Total (in shares)	2,000,000
2010 ECP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding (in shares)	250,498
RSUs Outstanding (in shares)	946,538
Options and RSUs Exercised (in shares)	2,780,740
Available Shares (in shares)	604,242
Total (in shares)	4,582,018
2005 LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding (in shares)	13,748
RSUs Outstanding (in shares)	0
Options and RSUs Exercised (in shares)	950,085
Available Shares (in shares)	0
Total (in shares)	963,833