Earnings (Loss) Per Share Computation of earnings per share (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share Reconciliation [Abstract]
Net Income (Loss) Attributable to Parent	$ 32,479	$ 10,822	$ (3,076)	$ 33,958	$ (5,088)	$ (5,525)	$ (11,842)	$ 14,290	$ 74,183	$ (8,165)	$ (13,808)
Dilutive Securities, Effect on Basic Earnings Per Share, Dilutive Convertible Securities									4,927	0	0
Net Income (Loss) Available to Common Stockholders, Diluted									$ 79,110	$ (8,165)	$ (13,808)