Summary Of Significant Accounting Policies - Schedule of Cumulative Impact of Adoption (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Assets
Accounts receivable, net	$ 19,245	$ 199,626	$ 17,010
Other current assets	16,422	14,949	16,949
Long-term unbilled contracts receivable	65,013	106,913	2,930
Other assets	4,959	7,326	9,772
Liabilities
Accrued liabilities	24,254	48,401	47,969
Deferred revenue	4,106	1,903	2,686
Long-term deferred tax liabilities	64,545	79,605	15,085
Equity
Retained earnings	211,722	292,684	68,556
Calculated under Revenue Guidance in Effect before Topic 606
Assets
Accounts receivable, net			10,866
Other current assets	17,922		16,949
Long-term unbilled contracts receivable	2,091		2,930
Other assets	6,609		9,772
Liabilities
Accrued liabilities	25,019		47,969
Deferred revenue	4,838		2,686
Long-term deferred tax liabilities	9,225		15,085
Equity
Retained earnings	36,026		$ 68,556
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Assets
Accounts receivable, net		188,760
Other current assets	(1,500)	(2,000)
Long-term unbilled contracts receivable	62,922	103,983
Other assets	(1,650)	(2,446)
Liabilities
Accrued liabilities	(765)	432
Deferred revenue	(732)	(783)
Long-term deferred tax liabilities	55,320	64,520
Equity
Retained earnings	$ 175,696	$ 224,128