Quarterly report pursuant to Section 13 or 15(d)

SENIOR NOTES, NET - Narrative (Details)

v3.8.0.1
SENIOR NOTES, NET - Narrative (Details) - Senior Notes [Member] - USD ($)
3 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Jun. 30, 2015
6.00% senior notes due 2025 [Member]      
Debt Instrument [Line Items]      
Aggregate Principal $ 400,000,000.0    
Stated interest rate 6.00% 6.00% 6.00%
Senior notes, gross $ 405,932,000 [1] $ 200,000,000 [1] $ 200,000,000
6.00% additional senior notes due 2025 [Member]      
Debt Instrument [Line Items]      
Aggregate Principal $ 200,000,000.0    
Stated interest rate 6.00%    
Percentage of premium on debt 103.00%    
4.50% senior notes due 2018 [Member]      
Debt Instrument [Line Items]      
Stated interest rate 4.50% 4.50%  
Senior notes, gross $ 0 $ 175,000,000  
Repayments of Debt $ 175,000,000    
[1] The $200.0 million 6.00% Senior Notes due 2025 outstanding at December 31, 2017 were issued at par and had no unamortized premium.