Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2014

Fair Value Disclosures [Abstract]

Schedule of Fair Value of Financial Instruments, Non-Recurring Measurements

Carrying amounts and estimated fair values of selected financial instruments measured on a non-recurring basis as of the dates indicated were as follows (in millions):

	December 31, 2014				December 31, 2013
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
4.875% Senior Notes	$	400.0	$	375.0	$	400.0	$	380.0
2009 Convertible Notes	$	—	$	—	$	12.6	$	26.6
2011 Convertible Notes	$	—	$	—	$	198.3	$	428.3