Quarterly Financial Data (unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Quarterly Financial Data (unaudited)
Net revenue	$ 214,985	$ 197,030	$ 140,988	$ 149,573	$ 190,107	$ 175,621	$ 129,632	$ 137,427	$ 702,576	$ 632,787	$ 587,964
Gross profit	64,321	58,505	32,411	37,245	56,702	52,358	31,565	34,442	192,482	175,067	145,933
Net income (loss)	$ 10,253	$ 11,016	$ (8,260)	$ (5,872)	$ (4,906)	$ (13,036)	$ (20,558)	$ (23,748)	$ 7,137	$ (62,248)	$ (229,921)
Basic and diluted earnings (loss) per share	$ 0.14	$ 0.15	$ (0.11)	$ (0.09)	$ (0.08)	$ (0.21)	$ (0.34)	$ (0.39)	$ 0.10	$ (1.02)	$ (3.80)