Share-Based Compensation (Details 2) (USD $)	6 Months Ended
	Jun. 30, 2013
Restricted stock activity
Restricted shares outstanding, beginning of period, weighted average price	$ 33.38
Restricted shares outstanding, beginning of period, shares	896,164
Restricted shares granted, weighted average price	$ 15.36
Restricted shares granted, shares	630,930
Restricted shares canceled, weighted average price	$ 24.68
Restricted shares canceled, shares	(16,271)
Restricted shares vested, weighted average price	$ 32.85
Restricted shares vested, shares	(366,905)
Restricted shares outstanding, end of period, weighted average price	$ 23.74
Restricted shares outstanding, end of period, shares	1,143,918