Deferred Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Deferred costs	$ 29,100	$ 18,700
Amortization expense for deferred costs	15,200	10,100
Impairment loss	$ 0	$ 0