SIGNIFICANT ACCOUNTING POLICIES AND RECENT ACCOUNTING PRONOUNCEMENTS Prior Period Income Statement Adjustments, Adoption of ASU 2014-09 (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Condensed Consolidated Income Statement Data
NET REVENUES		$ 104,688	$ 88,036
COST OF REVENUES		54,212	43,548
PROVISION FOR (BENEFIT FROM) INCOME TAXES		(677)	335
NET INCOME		$ 14,099	$ 10,379
Basic (in dollars per share)		$ 0.48	$ 0.36
Diluted (in dollars per share)	[1]	$ 0.47	$ 0.35
Adjustments for Accounting Standards Update 2014-09 [Member]
Condensed Consolidated Income Statement Data
NET REVENUES			$ 2,710
COST OF REVENUES			1,169
PROVISION FOR (BENEFIT FROM) INCOME TAXES			5
NET INCOME			$ 1,536
Basic (in dollars per share)			$ 0.05
Diluted (in dollars per share)			$ 0.05
As Reported
Condensed Consolidated Income Statement Data
NET REVENUES			$ 85,326
COST OF REVENUES			42,379
PROVISION FOR (BENEFIT FROM) INCOME TAXES			330
NET INCOME			$ 8,843
Basic (in dollars per share)			$ 0.31
Diluted (in dollars per share)			$ 0.30

[1] The Company includes the shares underlying performance-based awards in the calculation of diluted earnings per share if the performance conditions have been satisfied as of the end of the reporting period and excludes such shares when the necessary conditions have not been met. The Company has excluded the shares underlying the outstanding performance-based awards in the 2017 and 2016 calculations as the shares were not contingently issuable as of the end of the reporting periods.