Consolidated Statements of Stockholders' Equity (USD $)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings (Accumulated Deficit) [Member]	Accumulated Other Comprehensive Income [Member]	Parent [Member]	Noncontrolling Interest [Member]	Total Equity [Member]
Beginning Balance, Equity at Dec. 31, 2011		$ 64,000	$ 1,388,253,000		$ (698,704,000)	$ 12,928,000	$ 702,541,000	$ (3,074,000)	$ 699,467,000
Beginning Balance, Shares, Outstanding at Dec. 31, 2011		644,145,201
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(51,031,000)				(54,773,000)		(54,773,000)	3,748,000	(51,025,000)
Foreign currency translation adjustments	(425,000)					(535,000)	(535,000)	960,000	425,000
Pension liability adjustment	0
Unrealized gain (loss) on available-for-sale debt security, net of tax						53,000	53,000		53,000
Adjustment of redeemable noncontrolling interests to redemption value	(12,604,000)	0	(12,604,000)				(12,604,000)	0	(12,604,000)
Common stock issued in connection with acquisition of business, shares		152,446
Purchases of additional interests in consolidated subsidiaries, shares		51,000
Shares issued to settle liability-classified awards, shares	660,539	660,539
Shares issued to settle liability-classified awards and contingent consideration	2,267,000		2,503,000				2,503,000		2,503,000
Purchase of noncontrolling interest, excess of purchase price over value of noncontrolling interest			(2,584,000)				(2,584,000)
Purchase of interests in consolidated subsidiaries								739,000
Purchase of noncontrolling interests in consolidated subsidiaries									(1,845,000)
Exercise of stock options, shares		9,025,164
Exercise of stock options, value		1,000	9,312,000				9,313,000		9,313,000
Vesting of restricted stock units, shares		4,452,979
Tax withholding related to net share settlements of stock-based compensation awards, shares		(1,563,647)
Tax withholding related to net share settlements of stock-based compensation awards, value			(14,918,000)				(14,918,000)		(14,918,000)
Stock-based compensation on equity-classified awards			93,781,000				93,781,000		93,781,000
Excess tax benefits on stock-based compensation awards			21,263,000				21,263,000		21,263,000
Partnership distributions to noncontrolling interest holders								(4,312,000)	(4,312,000)
Ending Balance, Equity at Dec. 31, 2012		65,000	1,485,006,000		(753,477,000)	12,446,000	744,040,000	(1,939,000)	742,101,000
Ending Balance, Shares, Outstanding at Dec. 31, 2012		656,923,682
Beginning Balance, Treasury Stock, Value at Dec. 31, 2012				0
Beginning Balance, Treasury Stock, Shares at Dec. 31, 2012				0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(88,946,000)				(95,393,000)		(95,393,000)	6,447,000	(88,946,000)
Foreign currency translation adjustments	(12,933,000)					12,559,000	12,559,000	374,000	12,933,000
Pension liability adjustment	0
Unrealized gain (loss) on available-for-sale debt security, net of tax						(175,000)	(175,000)		(175,000)
Adjustment of redeemable noncontrolling interests to redemption value	0
Common stock issued in connection with acquisition of business, shares		276,217
Common stock issued in connection with acquisition of business, net of issuance costs		0	3,051,000				3,051,000		3,051,000
Shares issued to settle liability-classified awards, shares		758,474
Shares issued to settle liability-classified awards and contingent consideration	4,649,000		4,649,000				4,649,000		4,649,000
Exercise of stock options, shares		4,003,544
Exercise of stock options, value			4,062,000				4,062,000		4,062,000
Vesting of restricted stock units, shares		15,565,805
Vesting of restricted stock units, value		2,000	(2,000)
Shares issued under employee stock purchase plan, shares		774,288
Shares issued under employee stock purchase plan, value			3,241,000				3,241,000		3,241,000
Tax withholding related to net share settlements of stock-based compensation awards, shares		(5,752,058)
Tax withholding related to net share settlements of stock-based compensation awards, value			(47,684,000)				(47,684,000)		(47,684,000)
Stock-based compensation on equity-classified awards			122,222,000				122,222,000		122,222,000
Excess tax benefits on stock-based compensation awards			9,666,000				9,666,000		9,666,000
Purchases of treasury stock, shares				(4,432,800)
Purchases of treasury stock, value				(46,587,000)			(46,587,000)		(46,587,000)
Partnership distributions to noncontrolling interest holders								(6,851,000)	(6,851,000)
Ending Balance, Equity at Dec. 31, 2013	711,682,000	67,000	1,584,211,000		(848,870,000)	24,830,000	713,651,000	(1,969,000)	711,682,000
Ending Balance, Treasury Stock, Value at Dec. 31, 2013	(46,587,000)			(46,587,000)
Ending Balance, Treasury Stock, Shares at Dec. 31, 2013				(4,432,800)
Ending Balance, Shares, Outstanding at Dec. 31, 2013		672,549,952
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(63,919,000)				(73,090,000)		(73,090,000)	9,171,000	(63,919,000)
Foreign currency translation adjustments	(11,625,000)					11,812,000	11,812,000	(187,000)	11,625,000
Pension liability adjustment	(1,500,000)					(1,500,000)	(1,500,000)	0	(1,500,000)
Unrealized gain (loss) on available-for-sale debt security, net of tax						621,000	621,000		621,000
Adjustment of redeemable noncontrolling interests to redemption value	0
Common stock issued in connection with acquisition of business, shares		15,255,180
Common stock issued in connection with acquisition of business, net of issuance costs		2,000	173,813,000				173,815,000		173,815,000
Shares issued to settle liability-classified awards, shares		102,180
Shares issued to settle liability-classified awards and contingent consideration	1,041,000		1,041,000				1,041,000		1,041,000
Purchase of noncontrolling interest, excess of purchase price over value of noncontrolling interest			(6,310,000)				(6,310,000)
Purchase of interests in consolidated subsidiaries								2,415,000
Purchase of noncontrolling interests in consolidated subsidiaries									(3,895,000)
Exercise of stock options, shares		1,029,471
Exercise of stock options, value			1,118,000				1,118,000		1,118,000
Vesting of restricted stock units, shares		17,323,096
Vesting of restricted stock units, value		1,000	(1,000)
Shares issued under employee stock purchase plan, shares		857,171
Shares issued under employee stock purchase plan, value			5,396,000				5,396,000		5,396,000
Tax withholding related to net share settlements of stock-based compensation awards, shares		(5,708,990)
Tax withholding related to net share settlements of stock-based compensation awards, value			(44,509,000)				(44,509,000)		(44,509,000)
Stock-based compensation on equity-classified awards			133,230,000				133,230,000		133,230,000
Excess tax benefits on stock-based compensation awards			(569,000)				(569,000)		(569,000)
Purchases of treasury stock, shares				(22,806,304)
Purchases of treasury stock, value				(151,880,000)			(151,880,000)		(151,880,000)
Partnership distributions to noncontrolling interest holders								(7,312,000)	(7,312,000)
Ending Balance, Equity at Dec. 31, 2014	764,944,000	70,000	1,847,420,000		(921,960,000)	35,763,000	762,826,000	2,118,000	764,944,000
Ending Balance, Treasury Stock, Value at Dec. 31, 2014	$ (198,467,000)			$ (198,467,000)
Ending Balance, Treasury Stock, Shares at Dec. 31, 2014				(27,239,104)
Ending Balance, Shares, Outstanding at Dec. 31, 2014		701,408,060