Supplementary Balance Sheet Information (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Cash and cash equivalents in domestic accounts	$ 434,130	$ 405,535
Cash and cash equivalents in foreign accounts	60,516	65,621
Total cash and cash equivalents	494,646	471,156
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	496,811	474,279	$ 494,238	$ 451,370
Other long-term assets
Restricted cash included in other long-term assets	$ 2,165	$ 3,123