Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 20,591	$ 6,378	$ 18,930	$ 2,164
Unrealized gain on investments, net of tax	412	1,076	444	2,121
Comprehensive income	21,003	7,454	19,374	4,285
Comprehensive loss attributable to noncontrolling interest	(1,660)	(1,365)	(3,437)	(2,776)
Total comprehensive income attributable to InterDigital, Inc.	$ 22,663	$ 8,819	$ 22,811	$ 7,061