Consolidated Statements of Redeemable Noncontrolling Interests and Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Redeemable Noncontrolling Interests	Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Accumulated Deficit)	Total Stockholders' Equity	Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance, adjusted		$ 152,849
Beginning balance, adjusted	$ 746,021		$ 0	$ 10	$ 642,229	$ (921)	$ (881)	$ 640,437	$ 105,584
Beginning balance at Dec. 31, 2015		147,139
Beginning balance, (in shares) at Dec. 31, 2015			0	101,282
Beginning balance at Dec. 31, 2015	659,560		$ 0	$ 10	642,229	(921)	(87,249)	554,069	105,491
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)				1,852
Exercise of stock options	5,416				5,416			5,416
Issuance of restricted stock units, net of tax withholdings (in shares)				422
Issuance of restricted stock units, net of tax withholdings	(381)				(381)			(381)
Shares issued in connection with the Employee Stock Purchase Plan (in shares)				515
Shares issued in connection with the Employee Stock Purchase Plan	2,432				2,432			2,432
Stock-based compensation	18,817				18,817			18,817
Contributions from noncontrolling interests and redeemable noncontrolling interests	450,519	123,023							450,519
Distributions to noncontrolling interests and redeemable noncontrolling interests	(28,448)	(13,606)							(28,448)
Issuance of shares due to business acquisition in 2015 (in shares)				250
Issuance of shares due to business acquisition in 2015	0				0
Offering costs in connection with underwritten public offering	(437)				(437)			(437)
Net income (loss)	(199,569)	(121,270)					75,129	75,129	(274,698)
Other comprehensive income (loss), net of taxes	1,358					1,358		1,358
Ending balance at Dec. 31, 2016	$ 995,728		$ 0	$ 10	668,076	437	74,248	742,771	252,957
Ending balance at Dec. 31, 2016		140,996
Ending balance, (in shares) at Dec. 31, 2016			0	104,321
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)	687			686
Exercise of stock options	$ 1,984				1,984			1,984
Issuance of restricted stock units, net of tax withholdings (in shares)				1,115
Issuance of restricted stock units, net of tax withholdings	(3,569)				(3,569)			(3,569)
Shares issued in connection with the Employee Stock Purchase Plan (in shares)				628
Shares issued in connection with the Employee Stock Purchase Plan	2,620			$ 1	2,619			2,620
Stock-based compensation	22,088				22,088			22,088
Contributions from noncontrolling interests and redeemable noncontrolling interests	469,617	128,052							469,617
Distributions to noncontrolling interests and redeemable noncontrolling interests	(42,690)	(14,769)							(42,690)
Issuance of shares due to business acquisition in 2015 (in shares)				600
Issuance of shares due to business acquisition in 2015	0
Net income (loss)	(195,055)	(92,559)					125,490	125,490	(320,545)
Other comprehensive income (loss), net of taxes	(4,550)					(4,550)		(4,550)
Ending balance at Dec. 31, 2017	1,240,516		$ 0	$ 11	682,950	(4,113)	202,734	881,582	358,934
Ending balance at Dec. 31, 2017	$ 123,801	123,801
Ending balance, (in shares) at Dec. 31, 2017			0	107,350
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)	3,271			3,271
Exercise of stock options	$ 17,178				17,178			17,178
Issuance of restricted stock units, net of tax withholdings (in shares)				1,614
Issuance of restricted stock units, net of tax withholdings	(10,102)				(10,102)			(10,102)
Shares issued in connection with the Employee Stock Purchase Plan (in shares)				914
Shares issued in connection with the Employee Stock Purchase Plan	4,546			$ 0	4,546			4,546
Stock-based compensation	27,857				27,857			27,857
Acquisition of noncontrolling interests	(8,653)	(37,919)			(8,248)			(8,248)	(405)
Contributions from noncontrolling interests and redeemable noncontrolling interests	234,022	111,125							234,022
Distributions to noncontrolling interests and redeemable noncontrolling interests	(69,605)	(11,057)							(69,605)
Net income (loss)	(162,619)	(97,567)					26,657	26,657	(189,276)
Other comprehensive income (loss), net of taxes	989
Other comprehensive loss, net of taxes	(1,003)					(1,003)		(1,003)
Ending balance at Dec. 31, 2018	1,282,782		$ 0	$ 11	$ 722,429	$ (3,124)	$ 229,391	$ 948,707	$ 334,075
Ending balance at Dec. 31, 2018	$ 126,302	$ 126,302
Ending balance, (in shares) at Dec. 31, 2018			0	113,149