Basis Of Presentation And New Accounting Standards (Details) - USD ($) $ in Thousands		3 Months Ended
	Jan. 01, 2018	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Assets
Unbilled and other		$ 43,353		$ 29,947
Other current assets		46,236		41,768
Liabilities
Deferred tax liabilities		108,546		103,349
Equity
Retained earnings		351,876		$ 352,906
Statement of Operations
Net revenues		164,262	$ 104,528
Loss from operations		(1,116)	(17,705)
Loss before income taxes		(2,473)	(21,016)
Income tax provision (benefit)		87	(4,601)
Net loss		(2,560)	$ (16,415)
Pro Forma Without Adoption of ASC 606
Assets
Unbilled and other		43,461
Other current assets		45,340
Liabilities
Deferred tax liabilities		108,391
Equity
Retained earnings		351,243
Statement of Operations
Net revenues		163,474
Loss from operations		(1,904)
Loss before income taxes		(3,261)
Income tax provision (benefit)		(68)
Net loss		(3,193)
Effect of Change | ASC 606
Assets
Unbilled and other		(108)
Other current assets		896
Liabilities
Deferred tax liabilities		155
Equity
Retained earnings		633
Statement of Operations
Net revenues		788
Loss from operations		788
Loss before income taxes		788
Income tax provision (benefit)		155
Net loss		$ 633
Accumulated OCI | ASU No. 2018-02
Statement of Operations
Reclassification of net stranded tax benefits	$ (1,500)
Retained Earnings | ASU No. 2018-02
Statement of Operations
Reclassification of net stranded tax benefits	$ 1,500