NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Share Repurchase Program and Advertising Expense (Details) - USD ($) shares in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Mar. 20, 2014	Oct. 28, 1999
Share Repurchase Program
Share repurchase program, authorized amount				$ 150,000,000.0	$ 150,000,000.0
Number of shares repurchased	1.1
Value of shares repurchased	$ 28,800,000	$ 133,157,000
Total remaining authorization amount	105,500,000.0
Advertising Expenses
Total advertising expenses	$ 23,900,000	$ 21,300,000	$ 15,400,000