1st Global Acquisition - Fair Values of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Goodwill	$ 391,084	$ 662,375
Purchase accounting adjustment	(666)
Adjustments to other current liabilities	281
Adjustments to deferred income tax liabilities	385
1st Global
Business Acquisition [Line Items]
Tangible assets acquired, including cash of $12,389	38,413	38,413
Cash	12,389
Goodwill	117,126	117,792
Identifiable intangible assets	83,980	83,980
Contingent liability	(11,052)	(11,052)
Deferred revenues	(17,715)	(17,715)
Other current liabilities	(12,675)	(12,956)
Deferred tax liabilities, net	(18,077)	(18,462)
Total assets acquired and liabilities assumed	180,000	$ 180,000
Purchase accounting adjustment	$ (666)