For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13531-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6404-108592

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13537-108611

Name:	us-gaap_ConcentrationRiskPercentage1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Commitments and Contingencies (Concentrations of Risk) (Narrative) (Details) - customer			3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Concentration Risk [Line Items]
Number of customers			310
Credit Concentration Risk [Member] \| Customer with Highest Net Accounts Receivable Position [Member] \| Accounts Receivable, Net, Less Billings in Excess of Costs and Earnings [Member]
Concentration Risk [Line Items]
Number of customers	1
Concentration risk, percentage of total	14.00%	12.00%
Customer Concentration Risk [Member] \| Ten Largest Customers [Member] \| Revenue [Member]
Concentration Risk [Line Items]
Number of customers			10	10
Concentration risk, percentage of total			73.00%	60.00%