Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 286,119	$ 746,655
Holding (losses) gains associated with marketable securities arising during period, net of tax	(548)	609
Ending balance	263,738	614,719
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(3,239)	(3,985)
Ending balance	$ (3,787)	$ (3,376)