Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Other assets:
Long-term investments	$ 425,732	$ 412,369
Other	99,041	113,522
Total	524,773	525,891
Accounts payable and accrued liabilities:
Accounts payable	293,538	302,113
Customer deposits	688,772	665,339
Employee related liabilities	205,901	255,893
Other	190,611	224,976
Total	$ 1,378,822	$ 1,448,321