Common Stock (Stock-Based Incentive Plans) (Details)	Dec. 31, 2012
2010 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares that may be issued	6,000,000
Shares remaining to be granted	1,200,000
2007 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares that may be issued	2,200,000
Shares remaining to be granted	100,000
2005 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares that may be issued	1,900,000
Shares remaining to be granted	100,000
2003 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares that may be issued	1,400,000