Long-Term Debt - Components Of Net Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Debt Disclosure [Abstract]
Interest expense	$ 7,896	$ 8,299
Interest income	(758)	(590)
Capitalized interest	(5,040)	(3,813)
Net interest expense	$ 2,098	$ 3,896