Notes Payable (Other Debt Information) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Debt Disclosure [Abstract]
Notes payable, fair value	$ 1,100,000		$ 1,100,000
Total interest incurred	11,835	$ 10,874
Interest capitalized	(1,015)	(1,096)
Total interest expense	$ 10,820	$ 9,778