Basis Of Presentation And Significant Accounting Policies - Allowance For Doubtful Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Allowance for doubtful accounts and billing adjustments [Roll Forward]
Provision	$ 1,200
Allowance for Doubtful Accounts
Allowance for doubtful accounts and billing adjustments [Roll Forward]
Balance	270	[1]	513	[1]	748	[1]
Provision	571	[1]	(150)	[1]	224	[1]
Write-offs and recoveries, net	(577)	[1]	(93)	[1]	(459)	[1]
Balance	264	[1]	270	[1]	513	[1]
Reserves for Billing Adjustments and Contractual Allowances
Allowance for doubtful accounts and billing adjustments [Roll Forward]
Balance	8	[2]	81	[2]	356	[2]
Provision	99	[2]	29	[2]	232	[2]
Write-offs and recoveries, net	(100)	[2]	(102)	[2]	(507)	[2]
Balance	7	[2]	8	[2]	81	[2]
Reserves for Contractual Allowance [Member]
Allowance for doubtful accounts and billing adjustments [Roll Forward]
Balance	0		0		0
Provision	18,675		0		0
Write-offs and recoveries, net	(17,968)		0		0
Balance	$ 707		$ 0		$ 0

[1] The provision was charged against general and administrative expenses.

[2] The provision was charged against Diagnostic Services revenue.