Quarterly report pursuant to Section 13 or 15(d)

DEBT AND CREDIT FACILITIES DEBT AND CREDIT FACILITIES - BORROWING CAPACITY (Details)

v3.19.1
DEBT AND CREDIT FACILITIES DEBT AND CREDIT FACILITIES - BORROWING CAPACITY (Details) - USD ($)
Mar. 31, 2019
Dec. 31, 2018
Revolving Credit Facility [Member]    
Line of Credit Facility [Line Items]    
Line of Credit Facility, Maximum Borrowing Capacity $ 305,400,000 $ 323,700,000
Long-term Line of Credit 0 0
Line of Credit Facility, Remaining Borrowing Capacity 240,000,000 268,700,000
Letter of Credit [Member]    
Line of Credit Facility [Line Items]    
Long-term Line of Credit $ 65,400,000 $ 55,000,000