STOCK AWARD PLANS - Employee Stock Purchase Plan Activity (Details) - USD ($)	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares purchased by employees (shares)	98,839
Aggregate cost to employees	$ 5,561,671
Expense recognized by the company	11,397,000	$ 17,123,000
Company expense on ESPP discount
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense recognized by the company	$ 981,471	$ 1,130,000

Number of shares issued during the period as a result of an employee stock purchase plan.

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Name:	us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration