SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Long-Lived Assets By Country (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Long Lived Assets [Line Items]
Long-Lived Assets	$ 47,725	$ 52,667
USA
Long Lived Assets [Line Items]
Long-Lived Assets	28,089	27,400
United Kingdom
Long Lived Assets [Line Items]
Long-Lived Assets	18,431	23,006
Other
Long Lived Assets [Line Items]
Long-Lived Assets	$ 1,205	$ 2,261