Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income	$ 2,478,806	$ 2,266,095	$ 2,127,941	$ 1,260,946	$ 1,194,951	$ 1,111,199
Foreign currency translation adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income	18,068		20,884
Net unrealized gain on investments, net of tax
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income	11,704		4,371
Accumulated other comprehensive income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income	$ 29,772	$ (14,380)	$ 25,255	$ 13,542	$ 10,323	$ (4,035)

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.