FAIR VALUE OF FINANCIAL INSTRUMENTS (Narrative) (Detail) - USD ($) $ in Thousands	1 Months Ended		12 Months Ended
	Mar. 31, 2013	Jan. 31, 2012	Dec. 31, 2017	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Cash payment received				$ 20,405
3.85% Senior notes due 2025
Derivative [Line Items]
Notional amount	$ 100,000
Stated interest rate	3.85%
Date of maturity			Feb. 26, 2025
Description of variable rate basis	LIBOR
Basis spread	1.77%
4.05% Senior notes due 2028
Derivative [Line Items]
Notional amount	$ 75,000
Stated interest rate	4.05%
Date of maturity			Feb. 26, 2028
Description of variable rate basis	LIBOR
Basis spread	1.73%
4.24% Senior notes due 2026
Derivative [Line Items]
Notional amount		$ 200,000
Stated interest rate		4.24%
Date of maturity			Dec. 01, 2026
Description of variable rate basis		LIBOR
Basis spread		2.02%
Issued amount of debt		$ 200,000
3.84% Senior notes due 2021
Derivative [Line Items]
Notional amount		$ 25,000
Stated interest rate		3.84%
Date of maturity			Dec. 01, 2021
Description of variable rate basis		LIBOR
Basis spread		1.90%
Issued amount of debt		$ 100,000