Income Taxes - Net Current and Net Long-Term Deferred Tax Assets and Liabilities by Tax Jurisdiction (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Deferred Tax Assets and Liabilities [Line Items]
Deferred Tax Assets, Current	$ 0		$ 0
Deferred Tax Assets, Long-term	2,055		1,146
Deferred Tax Liabilities, Current	0		0
Deferred Tax Liabilities, Long-term	39,265	$ 15,185	14,714
Federal
Deferred Tax Assets and Liabilities [Line Items]
Deferred Tax Assets, Current	0		0
Deferred Tax Assets, Long-term	0		0
Deferred Tax Liabilities, Current	0		0
Deferred Tax Liabilities, Long-term	30,193		7,288
State
Deferred Tax Assets and Liabilities [Line Items]
Deferred Tax Assets, Current	0		0
Deferred Tax Assets, Long-term	0		0
Deferred Tax Liabilities, Current	0		0
Deferred Tax Liabilities, Long-term	3,728		424
Foreign
Deferred Tax Assets and Liabilities [Line Items]
Deferred Tax Assets, Current	0		0
Deferred Tax Assets, Long-term	2,055		1,146
Deferred Tax Liabilities, Current	0		0
Deferred Tax Liabilities, Long-term	$ 5,344		$ 7,002