Stockholders' Equity (Narrative) (Details) (USD $)	12 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Parent [Member]	Dec. 31, 2013 Convertible senior notes due December 2020 [Member]	Nov. 21, 2013 Convertible senior notes due December 2020 [Member]
Common stock, shares authorized	125,000,000	125,000,000
Common stock, shares outstanding	44,375,952	44,641,224
Preferred stock, share authorized	10,000,000	10,000,000
Preferred stock, shares outstanding	0	0
Debt Instrument, Convertible, Carrying Amount of the Equity Component				$ 71,700,000	$ 71,700,000
Purchase of convertible note hedges	72,565,000		72,565,000
Proceeds from issuance of warrants	40,509,000		40,509,000
Deferred financing cost allocated to equity	$ 1,671,000