Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Statutory tax rate		21.00%
Federal tax loss		$ (5,628)	$ (5,965)
Deferred tax liability, intangible assets		$ 15,900	11,074
Expiration period		20 years
Valuation allowance		$ 392	864
Provisional income tax expense related to repricing of deferred tax balance		9,100
Provisional income taxes payable	$ 300	500
Federal
Operating Loss Carryforwards [Line Items]
Federal tax loss		66,600
Operating loss carryforwards		27,900
Operating loss carryforwards that do not expire		200
Income taxes on undistributed earnings on foreign subsidiaries		12,100
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards		27,900
United States and Canada
Operating Loss Carryforwards [Line Items]
Deferred tax liability, intangible assets		$ 15,900
Deferred tax liability, goodwill			$ 11,100