Contingently Issuable Common Stock (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	0 Months Ended		3 Months Ended		9 Months Ended
	Jun. 30, 2012	Dec. 10, 2010	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Business Combinations [Abstract]
Business acquisition, purchase price common shares		3.2
Business acquisition, common shares value		$ 19,400,000
Business acquisition, maximum shares issuable	4.2	10.2
Business acquisition, fair value of contingent payment		28,200,000	51,400,000		51,400,000
Business acquisition, closing stock price			$ 13.82		$ 13.82
Business acquisition, contingent consideration, at fair value hypothetical value			58,000,000		58,000,000
Business acquisition, increase (decrease) common stock					$ 2.34
Business acquisition, percentage increase (decrease)					20.00%
Fair Value of Contingently Issuable Common Stock [Roll Forward]
December 31, 2011					38,700,000
Fair value adjustment of Contingent Payment during the period			(990,000)	1,400,000	12,700,000	10,000,000
June 30, 2012		$ 28,200,000	$ 51,400,000		$ 51,400,000