Annual report pursuant to Section 13 and 15(d)

FAIR VALUE MEASUREMENTS - Narrative (Details)

v3.8.0.1
FAIR VALUE MEASUREMENTS - Narrative (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Unrealized losses forecasted to be included in earnings transferred from AOCI in the next twelve months $ 1.1  
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Aggregate notional amount $ 595.0 $ 425.0
Weighted average remaining term 3 years 6 months  
Weighted average fixed rate (percent) 1.51%  
Level 2 [Member] | Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed rate mortgages, fair value disclosure $ 282.6 $ 214.0
Weighted average market interest rate (percent) 4.04% 3.89%
Weighted average contractual interest rate (percent) 4.87% 5.25%
Reported Value Measurement [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed rate mortgages, fair value disclosure $ 271.5 $ 201.7