Stockholders' Equity (Narrative) (Details) (USD $)	0 Months Ended	1 Months Ended					3 Months Ended		9 Months Ended
	Nov. 06, 2012	Nov. 30, 2012	Nov. 30, 2012	Nov. 06, 2012	May 31, 2012	Oct. 31, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expenses recognized							$ 1,163,000	$ 881,000	$ 3,199,000	$ 2,130,000
Share repurchase program, approved increase		10,000,000			10,500,000
Share repurchase program, amount authorized			40,500,000		30,500,000	20,000,000
Stock repurchased and retired, shares				421,620			1,838,202		3,419,431
Stock repurchased and retired, value				2,500,000			9,500,000		18,400,000
Share repurchase program, remaining amount authorized	16,200,000								8,700,000
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, options granted, shares									1,887,000
Common stock, option exercises, shares									1,170,419
Unrecognized compensation expense, net of forfeitures							8,500,000		8,500,000
Unrecognized compensation expense, weighted-average remaining period for recognition, in years									2 years 7 months 17 days
Fair value assumption, method used to calculate grant date fair value per share									Black-Scholes option pricing model
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, option term									10 years
Stock-based compensation expenses recognized							(69,000)	0	(7,000)	100,000
RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, net of forfeitures							$ 1,300,000		$ 1,300,000
Unrecognized compensation expense, weighted-average remaining period for recognition, in years									1 year 9 months 11 days
RSUs granted, shares									190,000
RSUs, weighted average fair value at grant date									$ 6.49
RSUs vested, shares									43,863
Minimum [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value assumption, expected term, in years									5 years 2 months 19 days
Fair value assumption, minimum volatility factor									63.66%
Fair value assumption, minimum risk free interest rate									0.96%
Maximum [Member] | Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value assumption, expected term, in years									5 years 3 months 11 days
Fair value assumption, maximum volatility factor									65.14%
Fair value assumption, maximum risk free interest rate									1.96%