Income Taxes - Loss Carryforwards and Other (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2015	Dec. 31, 2016
Operating loss carryforwards
Valuation allowance	$ 3,500		$ 3,184
Net deferred tax assets	27,890		31,166
Reconciliation of the beginning and ending amount of unrecognized tax benefits, excluding accrued interest and penalties
Balance at beginning of year	240	$ 343
Additions based on tax positions related to current year	8,689
Reductions for tax positions related to prior years		(103)
Balance at end of year	8,929	$ 240
Interest and penalties accrued	700		$ 400
Unrecognized tax benefits that would impact effective tax rate	3,000
State and Puerto Rico
Operating loss carryforwards
Future tax benefits	6,000
Net operating loss carryforwards	71,800
Increase in valuation allowance	300
Net deferred tax assets	2,500
Maximum
Reconciliation of the beginning and ending amount of unrecognized tax benefits, excluding accrued interest and penalties
Decrease in unrecognized tax benefits	$ 8,700