CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common stock issued [Member]	Treasury stock [Member]	Additional paid-in capital [Member]	Retained earnings (accumulated deficit) [Member]	Accumulated other comprehensive loss [Member]	Non-controlling interest [Member]
Beginning Balance, Shares at Dec. 31, 2017	269,335		(88,504)
Beginning Balance at Dec. 31, 2017	$ 1,160,072	$ 2,693	$ (322,735)	$ 1,781,059	$ (338,150)	$ (1,985)	$ 39,190
Stock-based compensation				25,996
Common stock issued under stock compensation plans, net of shares withheld for employee taxes, Shares		1,471
Common stock issued under stock compensation plans, net of shares withheld for employee taxes		$ 15		(7,492)
Issuance of treasury stock, Shares			76
Issuance of treasury stock	1,121		$ 1,119	(61)
Accretion of redemption preference on redeemable convertible non-controlling interest - discontinued operations	(36,446)			(36,446)
Subsidiary issuance of common stock				0
Purchase of treasury stock, Shares			(7,671)
Purchase of treasury stock			$ (101,905)
Warrants issued				2,047
Net loss less net income attributable to non-controlling interests					25,405
ASC 606 implementation adjustments					58,225
ASC 606 implementation adjustments - discontinued operations					3,157
Foreign currency translation adjustments, net	(1,622)					(1,622)
Unrecognized gain on derivatives qualifying as cash flow hedges, net of tax						(1,845)
Acquisition of non-controlling interest				0			(6,492)
Net loss attributable to non-controlling interests	(3,494)						(3,494)
Ending Balance, Shares at Sep. 30, 2018		270,806	(96,099)
Ending Balance at Sep. 30, 2018	$ 1,116,679	$ 2,708	$ (423,521)	1,765,103	(251,363)	(5,452)	29,204
Beginning Balance, Shares at Dec. 31, 2017	269,335		(88,504)
Beginning Balance at Dec. 31, 2017	$ 1,160,072	2,693	$ (322,735)	1,781,059	(338,150)	(1,985)	39,190
Common stock issued under stock compensation plans, net of shares withheld for employee taxes, Shares	1,600
Ending Balance, Shares at Dec. 31, 2018	270,955		(99,731)
Ending Balance at Dec. 31, 2018	$ 1,580,427	2,709	$ (460,543)	1,881,494	132,842	(5,389)	29,314
Beginning Balance, Shares at Jun. 30, 2018	270,709		(96,175)
Beginning Balance at Jun. 30, 2018	$ 1,141,624	$ 2,707	$ (424,640)	1,766,863	(228,308)	(4,206)	29,208
Stock-based compensation				8,849
Common stock issued under stock compensation plans, net of shares withheld for employee taxes, Shares		97
Common stock issued under stock compensation plans, net of shares withheld for employee taxes		$ 1		918
Issuance of treasury stock, Shares			76
Issuance of treasury stock			$ 1,119	(61)
Accretion of redemption preference on redeemable convertible non-controlling interest - discontinued operations	(12,149)			(12,149)
Subsidiary issuance of common stock				0
Purchase of treasury stock, Shares			0
Purchase of treasury stock			$ 0
Warrants issued				683
Net loss less net income attributable to non-controlling interests					(23,842)
ASC 606 implementation adjustments					787
ASC 606 implementation adjustments - discontinued operations					0
Foreign currency translation adjustments, net	(60)					(60)
Unrecognized gain on derivatives qualifying as cash flow hedges, net of tax						(1,186)
Acquisition of non-controlling interest				0			0
Net loss attributable to non-controlling interests	(4)						(4)
Ending Balance, Shares at Sep. 30, 2018		270,806	(96,099)
Ending Balance at Sep. 30, 2018	$ 1,116,679	$ 2,708	$ (423,521)	1,765,103	(251,363)	(5,452)	29,204
Beginning Balance, Shares at Dec. 31, 2018	270,955		(99,731)
Beginning Balance at Dec. 31, 2018	$ 1,580,427	$ 2,709	$ (460,543)	1,881,494	132,842	(5,389)	29,314
Stock-based compensation				29,296
Common stock issued under stock compensation plans, net of shares withheld for employee taxes, Shares	1,500	1,541
Common stock issued under stock compensation plans, net of shares withheld for employee taxes		$ 15		(6,702)
Issuance of treasury stock, Shares			61
Issuance of treasury stock	$ 701		$ 846	(144)
Accretion of redemption preference on redeemable convertible non-controlling interest - discontinued operations	0			0
Subsidiary issuance of common stock				0
Purchase of treasury stock, Shares			(9,607)
Purchase of treasury stock			$ (102,160)
Warrants issued				2,047
Net loss less net income attributable to non-controlling interests					(163,208)
ASC 606 implementation adjustments					0
ASC 606 implementation adjustments - discontinued operations					0
Foreign currency translation adjustments, net	(35)					(35)
Unrecognized gain on derivatives qualifying as cash flow hedges, net of tax						(97)
Acquisition of non-controlling interest				(29,913)			(28,890)
Net loss attributable to non-controlling interests	$ (424)						(424)
Ending Balance, Shares at Sep. 30, 2019	272,496	272,496	(109,277)
Ending Balance at Sep. 30, 2019	$ 1,281,058	$ 2,724	$ (561,857)	1,876,078	(30,366)	(5,521)	0
Beginning Balance, Shares at Jun. 30, 2019	272,472		(105,818)
Beginning Balance at Jun. 30, 2019	$ 1,316,207	$ 2,724	$ (524,767)	1,867,613	(24,641)	(4,722)	0
Stock-based compensation				7,773
Common stock issued under stock compensation plans, net of shares withheld for employee taxes, Shares		24
Common stock issued under stock compensation plans, net of shares withheld for employee taxes		$ 0		9
Issuance of treasury stock, Shares			0
Issuance of treasury stock			$ 0	0
Accretion of redemption preference on redeemable convertible non-controlling interest - discontinued operations	0			0
Subsidiary issuance of common stock				0
Purchase of treasury stock, Shares			(3,459)
Purchase of treasury stock			$ (37,090)
Warrants issued				683
Net loss less net income attributable to non-controlling interests					(5,725)
ASC 606 implementation adjustments					0
ASC 606 implementation adjustments - discontinued operations					0
Foreign currency translation adjustments, net	(574)					(574)
Unrecognized gain on derivatives qualifying as cash flow hedges, net of tax						(225)
Acquisition of non-controlling interest				0			0
Net loss attributable to non-controlling interests	$ 0						0
Ending Balance, Shares at Sep. 30, 2019	272,496	272,496	(109,277)
Ending Balance at Sep. 30, 2019	$ 1,281,058	$ 2,724	$ (561,857)	$ 1,876,078	$ (30,366)	$ (5,521)	$ 0