Business Segments Total Assets by Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 2,687,851	$ 1,810,129
Apex
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	1,368,548	1,357,246
Oxford
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	421,199	424,593
ECS
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	865,610	0
Corporate
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 32,494	$ 28,290