Quarterly report pursuant to Section 13 or 15(d)

CONSOLIDATED CONDENSED BALANCE SHEETS (Parenthetical)

v3.8.0.1
CONSOLIDATED CONDENSED BALANCE SHEETS (Parenthetical) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Statement of Financial Position [Abstract]    
Allowance for bad debts $ 7,596 $ 7,564
Accumulated depreciation and amortization on property, plant and equipment 1,353,509 1,343,105
Debt issuance costs $ 6,596 $ 7,029
Preferred stock, par value (in dollars per share) $ 1.00 $ 1
Preferred stock, shares authorized 1,942,000 1,942,000
Preferred dividend percentage 7.25% 7.25%
Preferred stock, shares issued 500,000 500,000
Preferred stock, shares outstanding 500,000 500,000
Common stock, par value (in dollars per share) $ 0.166667 $ 0.166667
Common stock, shares authorized 280,000,000 280,000,000
Common stock, shares issued 139,249,563 138,935,734
Common stock, shares outstanding 139,249,563 138,935,734