Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 2,332	$ 2,332
Preferred stock, par value	$ 1.00	$ 1.00
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.20	$ 0.20
Common stock, shares authorized	175,000,000	175,000,000
Common stock, shares issued	54,746,727	55,443,393
VIE Current Assets Pledged	$ 46,700	$ 28,800
VIE Non-current Assets Pledged	360,700	434,300
VIE Current Liabilities, No Recourse	25,800	32,200
VIE Non-current Liabilities, No Recourse	$ 42,900	$ 26,000