Impairment of Long-Lived Assets and Goodwill (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Impairment Of Long Lived Assets And Goodwill [Abstract]
Impairment of long-lived assets and goodwill	$ 8,010	$ 26,000	$ 8,900	$ 32,438	$ 0	$ 39,800	$ 42,820	$ 72,198
Impairment of long-lived assets	7,400	15,300	8,400	31,500	$ 0	34,700
Impairment of capitalized software costs	$ 600	4,200	$ 500	$ 900		$ 5,100
Impairment of goodwill		$ 6,500					$ 6,490