NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Share Repurchase Program (Details) - USD ($) shares in Millions	1 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2017	Mar. 20, 2014
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount				$ 150,000,000.0
Stock repurchase program, additional authorized repurchase amount	$ 150,000,000
Class A Common Stock
Equity, Class of Treasury Stock [Line Items]
Treasury stock, shares acquired (in shares)		1.0	1.0
Treasury stock, value acquired		$ 30,300,000	$ 30,300,000
Stock repurchase program, remaining authorized repurchase amount		$ 88,800,000	$ 88,800,000