Revenue Recognition (Schedule of Changes in Contract Balances and Impacts of Entries to Adopt ASC 606) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
Accounts receivable, net
Beginning balance	$ 418,911	[1]
$ change	$ (59,929)
% change	(14.30%)
Ending balance	$ 358,982
Contract liabilities - current
Beginning balance	30,103	[1]
$ change	$ 5,382
% change	17.90%
Ending balance	$ 35,485
Contract liabilities - non-current
Beginning balance	13,839	[1]
$ change	$ 6,309
% change	45.60%
Ending balance	$ 20,148

[1] Includes the adjustments made to the contracts which were not completed at the date of ASC 606 adoption using the modified retrospective method.