EQUITY - Common Stock (Details) - USD ($)		3 Months Ended	9 Months Ended
	Feb. 25, 2019	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Mar. 21, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Average price per share (in dollars per share)					$ 25.00
Tax withholding obligations incurred on behalf of employees			$ 1,300,000	$ 200,000
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued upon vesting (in shares)			115,572
ATM Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate gross proceeds possible from sales of common stock under equity distribution agreement (up to)	$ 500,000,000.0
Commission rate (up to)	1.50%
Shares sold under the ATM Program (in shares)		4,200,000	15,300,000
Sale of stock, average price per share (in dollars per share)		$ 21.82	$ 20.20
Gross proceeds from issuance of common stock		$ 91,200,000	$ 308,500,000
Payments for stock issuance commissions		1,300,000	4,600,000
Amount available under ATM Program		$ 191,500,000	$ 191,500,000