THE COMPANY AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Adoption of ASU 2014-09 (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue by segment:	$ 303,116	$ 181,717	$ 853,249	$ 513,173
Operating costs and expenses by segment:	269,601	294,222	807,228	627,126
Operating loss	33,515	(112,505)	46,021	(113,953)
Net earnings	26,786	$ (72,158)	40,695	$ (46,296)
North America
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue by segment:	286,594
Operating costs and expenses by segment:	250,477		743,263
Operating loss	36,117
Europe
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue by segment:	16,522
Operating costs and expenses by segment:	19,124		63,965
Operating loss	(2,602)
Under ASC 605
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue by segment:	303,116		853,249
Operating costs and expenses by segment:	269,352		815,190
Operating loss	33,764		38,059
Net earnings	26,933		34,664
Under ASC 605 | North America
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue by segment:	286,594		800,125
Operating costs and expenses by segment:	250,286		751,177
Operating loss	36,308		48,948
Under ASC 605 | Europe
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue by segment:	16,522		53,124
Operating costs and expenses by segment:	19,066		64,013
Operating loss	(2,544)		(10,889)
Accounting Standards Update 2014-09 | Effect of adoption of ASU No. 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue by segment:	0		0
Operating costs and expenses by segment:	249		(7,962)
Operating loss	(249)		7,962
Net earnings	(147)		6,031
Accounting Standards Update 2014-09 | Effect of adoption of ASU No. 2014-09 | North America
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue by segment:	0		0
Operating costs and expenses by segment:	191		(7,914)
Operating loss	(191)		7,914
Accounting Standards Update 2014-09 | Effect of adoption of ASU No. 2014-09 | Europe
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue by segment:	0		0
Operating costs and expenses by segment:	58		(48)
Operating loss	$ (58)		$ 48