Dispositions and Discontinued Operations (Schedule of Amounts Attributable to Each Category of Discontinued Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disposal Group Not Discontinued Operation Income Statement Disclosures [Abstract]
Revenues before reimbursements		$ 87,169		$ 169,603
Total revenues		91,013		177,465
Cost of services including reimbursable expenses		60,168		118,655
General and administrative expenses		8,770		16,053
Amortization and depreciation expense		1,931		3,884
Interest expense		600		1,088
Income from disposition of discontinued operations	$ 721		$ 49
Other expense, net		28		57
Income from discontinued operations before income tax expense	721	19,516	49	37,728
Income tax (benefit) expense from discontinued operations	198	(3,182)	15	1,580
Income from discontinued operations, net of tax	$ 523	$ 22,698	$ 34	$ 36,148