Earnings Per Common Share (EPS) (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Goodwill, Impairment Loss	$ 379,863	$ 0	$ 379,863	$ 0
Net income (loss)	$ (315,439)	$ 27,896	$ (310,717)	$ 16,954
Earnings Per Share, Diluted	$ (6.38)	$ 0.49	$ (6.40)	$ 0.25
Scenario Unfavorable Adjustment [Member]
Net income (loss)	$ 329,500		$ 329,500
Earnings Per Share, Diluted	$ 6.56		$ 6.57