Income (Loss) Per Share - Calculation of Basic and Diluted Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Basic net income (loss) per share attributable to common stockholders:
Net loss attributable to common stockholders	$ (166,144)	$ (15,747)	$ 26,769
Weighted-average common shares outstanding	129,024	122,800	113,643
Basic (in dollars per share)	$ (1.29)	$ (0.13)	$ 0.24
Diluted net income (loss) per share attributable to common stockholders:
Net loss attributable to common stockholders	$ (166,144)	$ (15,747)	$ 26,769
Number of shares used in diluted calculation (in shares)	129,024	122,800	118,944
Diluted (in dollars per share)	$ (1.29)	$ (0.13)	$ 0.23
Class A Common Stock [Member]
Basic net income (loss) per share attributable to common stockholders:
Net loss attributable to common stockholders	$ (145,978)	$ (13,659)	$ 22,443
Weighted-average common shares outstanding	113,364	106,518	95,282
Basic (in dollars per share)	$ (1.29)	$ (0.13)	$ 0.24
Diluted net income (loss) per share attributable to common stockholders:
Net loss attributable to common stockholders	$ (145,978)	$ (13,659)	$ 22,443
Reallocation of undistributed earnings as a result of conversion of Class B to Class A shares	(20,166)	(2,088)	4,326
Reallocation of undistributed earnings to Class B shares	0	0	0
Allocation of undistributed earnings	$ (166,144)	$ (15,747)	$ 26,769
Conversion of Class B to Class A common shares outstanding (in shares)	15,660	16,282	18,361
Number of shares used in diluted calculation (in shares)	129,024	122,800	118,944
Diluted (in dollars per share)	$ (1.29)	$ (0.13)	$ 0.23
Class A Common Stock [Member] | Employee Stock Options [Member]
Diluted net income (loss) per share attributable to common stockholders:
Incremental common shares attributable to share-based payment arrangements (in shares)	0	0	4,128
Class A Common Stock [Member] | Restricted stock units [Member]
Diluted net income (loss) per share attributable to common stockholders:
Incremental common shares attributable to share-based payment arrangements (in shares)	0	0	1,173
Class B Common Stock [Member]
Basic net income (loss) per share attributable to common stockholders:
Net loss attributable to common stockholders	$ (20,166)	$ (2,088)	$ 4,326
Weighted-average common shares outstanding	15,660	16,282	18,361
Basic (in dollars per share)	$ (1.29)	$ (0.13)	$ 0.24
Diluted net income (loss) per share attributable to common stockholders:
Net loss attributable to common stockholders	$ (20,166)	$ (2,088)	$ 4,326
Reallocation of undistributed earnings as a result of conversion of Class B to Class A shares	0	0	0
Reallocation of undistributed earnings to Class B shares	0	0	713
Allocation of undistributed earnings	$ (20,166)	$ (2,088)	$ 5,039
Conversion of Class B to Class A common shares outstanding (in shares)	0	0	0
Number of shares used in diluted calculation (in shares)	15,660	16,282	22,386
Diluted (in dollars per share)	$ (1.29)	$ (0.13)	$ 0.23
Class B Common Stock [Member] | Employee Stock Options [Member]
Diluted net income (loss) per share attributable to common stockholders:
Incremental common shares attributable to share-based payment arrangements (in shares)	0	0	4,025
Class B Common Stock [Member] | Restricted stock units [Member]
Diluted net income (loss) per share attributable to common stockholders:
Incremental common shares attributable to share-based payment arrangements (in shares)	0	0	0