Summary of Significant Accounting Policies (Schedule of Adoption of New Accounting Pronouncements) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenues	$ 245,346	$ 227,401	$ 814,054	$ 679,441
Costs of services	(33,053)	(33,461)	(112,743)	(94,093)
Cost of inventory sold	(74,341)	(72,476)	(231,834)	(207,603)
Gross revenue, net of expenses		121,464		377,745
As Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenues		141,047		431,732
Costs of services		(19,583)		(53,987)
Gross revenue, net of expenses		121,464		377,745
New Revenue Standard Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenues		86,354		247,709
Costs of services		(13,878)		(40,106)
Cost of inventory sold		(72,476)		(207,603)
Service Revenues [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenues	161,374	145,938	551,736	442,066
Service Revenues [Member] | New Revenue Standard Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenues		4,891		10,334
Revenue from Inventory Sales [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenues	$ 83,972	81,463	$ 262,318	237,375
Revenue from Inventory Sales [Member] | New Revenue Standard Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total revenues		$ 81,463		$ 237,375