Acquisitions - Advantage RN (Details) - USD ($) $ in Thousands			3 Months Ended	6 Months Ended	12 Months Ended
	Jul. 28, 2017	Jul. 01, 2017	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Cash consideration					$ 85,977	$ 1,900	$ 28,721
Release of remaining contingent liability					(44)	(769)	0
Proceeds from Term Loans					62,000	40,000	0
Acquisition related costs					1,975	$ 78	$ 902
Advantage RN, LLC
Business Acquisition [Line Items]
Cash consideration		$ 86,562
Net working capital adjustment		600
Reimbursement from working capital adjustment settled			$ 800
Contingent liability				$ 300	300
Release of remaining contingent liability				300
Escrow payment related to tax liabilities		14,500
Escrow payment related to post-close liabilities		7,500
Release of escrow to seller	$ 7,300
Escrow deposit related to tax liabilities	$ 7,200
Consideration transferred, available cash		19,900
Revenue since acquisition				47,000
Net income since acquisition				$ 3,800
Assets acquired		$ 29,900
Weighted average useful life of assets acquired		10 years
Goodwill expected to be deductible		$ 43,600
Acquisition related costs					$ 2,000
Trade names | Advantage RN, LLC
Business Acquisition [Line Items]
Assets acquired		$ 4,500
Weighted average useful life of assets acquired		10 years
Customer relationships | Advantage RN, LLC
Business Acquisition [Line Items]
Assets acquired		$ 13,800
Weighted average useful life of assets acquired		10 years
Databases | Advantage RN, LLC
Business Acquisition [Line Items]
Assets acquired		$ 11,300
Weighted average useful life of assets acquired		10 years
Non-compete agreements | Advantage RN, LLC
Business Acquisition [Line Items]
Assets acquired		$ 300
Weighted average useful life of assets acquired		5 years
Deferred Consideration Transferred | Advantage RN, LLC
Business Acquisition [Line Items]
Contingent liability		$ 600
Period of deferred consideration		20 months
Credit Agreement
Business Acquisition [Line Items]
Proceeds from Term Loans		$ 66,900
Term Loan, net | Incremental Term Loan
Business Acquisition [Line Items]
Proceeds from Term Loans		40,000
Physician Staffing Segment | Advantage RN, LLC
Business Acquisition [Line Items]
Percent of business included in segment, less than				2.00%
Purchase Price | Advantage RN, LLC
Business Acquisition [Line Items]
Purchase price		$ 88,000