Supplemental balance sheet and cash flow information (supplemental cash flow information) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Cash and cash equivalents	$ 310,146	$ 73,620	$ 61,529
Total cash, cash equivalents, restricted cash and restricted cash equivalents	385,803	$ 174,811	138,500	$ 145,259
Funds held for customers [Member]
Restricted cash and restricted cash equivalents included in funds held for customers	$ 75,657		$ 76,971