BUSINESS COMBINATIONS - Purchase Price Allocation (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Jan. 01, 2017	Dec. 31, 2016	Oct. 03, 2016
Preliminary Recording of Assets Acquired and Liabilities Assumed
Goodwill	$ 184,557		$ 184,557
Creehan Holding Co., Inc.
Preliminary Recording of Assets Acquired and Liabilities Assumed
Cash and cash equivalents				$ 861
Accounts receivable				9,048
Other current assets				171
Property, equipment and capitalized software				641
Intangible assets				50,900
Goodwill	$ 184,557	$ 184,557		50,987
Total assets acquired				112,608
Current liabilities				(1,007)
Deferred revenue				(2,436)
Total liabilities assumed				(3,443)
Net assets acquired				$ 109,165