Earnings Per Share (Details) $ / shares in Units, shares in Thousands, $ in Thousands		1 Months Ended		3 Months Ended
	Feb. 01, 2017 $ / shares	Feb. 28, 2017	Jan. 31, 2017 $ / shares	Mar. 31, 2017 USD ($) $ / shares shares	Mar. 31, 2016 USD ($) $ / shares shares
Numerator:
Income from continuing operations | $				$ 70,325	$ 73,254
(Loss) income from discontinued operations, net of income taxes | $				(42,704)	10,209
Net income | $				$ 27,621	$ 83,463
Denominator:
Denominator for basic net earnings per share - weighted-average shares outstanding (shares) | shares				153,247	154,067
Effect of dilutive employee stock awards (shares) | shares				3,446	1,878
Effect of dilutive Convertible Notes (shares) | shares				1,676	0
Denominator for net diluted earnings per share - weighted-average shares outstanding (shares) | shares				158,369	155,945
Income from continuing operations, basic (in dollars per share)				$ 0.46	$ 0.47
(Loss) income from discontinued operations, basic (in dollars per share)				(0.28)	0.07
Basic earnings per share (in dollars per share)				0.18	0.54
Income from continuing operations, diluted (in dollars per share)				0.44	0.47
(Loss) income from discontinued operations, diluted (in dollars per share)				(0.27)	0.07
Diluted earnings per share (in dollars per share)				$ 0.17	$ 0.54
Anti-dilutive weighted-average shares from stock awards (shares) | shares				54	1,202
Senior Notes Due 2019 [Member]
Denominator:
Convertible debt, conversion price (in dollars per share)	$ 71.91		$ 90
Convertible debt, conversion ratio		0.0139061	0.011111
GetGo, Inc. [Member]
Denominator:
Convertible debt, conversion price (in dollars per share)	$ 71.91
Convertible debt, conversion ratio	0.0139061