Impairment of Long-Lived Assets and Goodwill (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Impairment Of Long Lived Assets And Goodwill [Abstract]
Impairment of long-lived assets and goodwill	$ 25,950	$ 8,900	$ 0	$ 39,800	$ 34,810	$ 39,760
Impairment of long-lived assets	15,300	8,400	$ 0	34,700
Impairment of capitalized software costs	4,200	$ 500		$ 5,100
Impairment of goodwill	$ 6,500				$ 6,490