EQUITY-BASED COMPENSATION - Performance-Based Restricted Stock Awards (Details) - Restricted Stock Awards $ / shares in Units, $ in Thousands					12 Months Ended
	Apr. 18, 2017 shares	Mar. 06, 2017 shares	Mar. 08, 2016 shares	Mar. 03, 2015 shares	Dec. 31, 2017 USD ($) Iteration $ / shares shares	Dec. 31, 2016 Iteration $ / shares shares	Dec. 31, 2015 Iteration $ / shares shares
Performance-Based
Assumptions used to estimate the fair value of options granted
Expected dividend yield (as a percent)					4.14%	4.01%	3.42%
Expected stock price volatility (as a percent)					24.80%	24.20%	22.20%
Risk-free interest rate (as a percent)					1.59%	1.04%	1.02%
Monte Carlo iterations | Iteration					100,000	100,000	100,000
Weighted average estimated fair value of awards granted | $ / shares					$ 17.13	$ 13.77	$ 18.78
Number of Shares
Non-vested at the beginning of year (in shares) | shares					449,027	308,367
Granted (in shares) | shares					210,361	254,563
Vested (in shares) | shares					(39,959)	(113,903)
Non-vested at end of year (in shares) | shares					619,429	449,027	308,367
Weighted Average Grant Date Fair Value
Non-vested at beginning of year (in dollars per share) | $ / shares					$ 14.90	$ 12.95
Granted (in dollars per share) | $ / shares					17.13	13.77	$ 18.78
Vested (in dollars per share) | $ / shares					7.12	7.10
Non-vested at end of year (in dollars per share) | $ / shares					$ 16.16	$ 14.90	$ 12.95
Aggregate Current Value
Non-vested outstanding | $					$ 9,434
Executive officers | Minimum
Equity-based compensation
Shares earned (as a percent)					0.00%
Executive officers | Maximum
Equity-based compensation
Shares earned (as a percent)					200.00%
Executive officers | Performance-Based
Number of Shares
Granted (in shares) | shares	30,322	180,039	254,563	154,505