Commitments And Contingencies (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) item	Dec. 31, 2014 USD ($) item	Dec. 31, 2013 USD ($)
Commitments And Contingencies [Abstract]
Office facility expense	$ 1,500	$ 1,500	$ 1,400
Number of outstanding letters of credit | item	1	1
Outstanding letter of credit	$ 100	$ 100
Rental equipment payable	10,901	$ 7,381
Commitments to purchase rental equipment	280,100
Commitments to purchase rental equipment, year one	123,000
Commitments to purchase rental equipment, year two	111,600
Commitments to purchase rental equipment, year three	$ 45,500