SCHEDULE II VALUATION AND QUALIFYING ACCOUNTS (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for doubtful receivables
VALUATION AND QUALIFYING ACCOUNTS
Balance at the beginning of the period	$ 4,379	$ 4,825	$ 4,514
Additions, Charged to costs and expenses	3,552	2,411	2,223
Deductions from reserves	(3,945)	(2,857)	(1,912)
Balance at the end of the period	3,986	4,379	4,825
Deferred tax valuation allowance
VALUATION AND QUALIFYING ACCOUNTS
Balance at the beginning of the period	808	101	172
Additions, Charged to costs and expenses	1,127	776
Deductions from reserves	(32)	(69)	(71)
Balance at the end of the period	$ 1,903	$ 808	$ 101

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Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 09

-Article 12

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- Definition

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- Definition

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