Other Noncurrent Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Liabilities, Other than Long-term Debt, Noncurrent [Abstract]
Tax amortization benefit contingency	$ 31,141	$ 29,369
Lease liability	5,509	0
Other	2,957	2,697
Total other noncurrent liabilities	$ 39,607	$ 32,066