Schedule I - Condensed Financial Information Of Registrant (Unconsolidated Balance Sheet) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	$ 48,152	$ 33,199
Total current assets	371,543	358,571
Other Assets, Noncurrent	22,082	10,971
TOTAL ASSETS	4,928,669	4,862,053	$ 4,740,561
Short-term debt	559,199	0
Accumulated deficit	(24,558)	(24,558)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	546,476	573,266	572,276	$ 571,183
Total common shareholder's deficit	606,260	633,050
Long-term debt	2,092,430	2,649,064
Other non-current liabilities	252	604
Accrued interest	35,334	34,790
Accrued and other current liabilities	49,860	27,787
Total current liabilities	882,215	302,557
Total non-current liabilities	3,440,194	3,926,446
Liabilities	4,322,409	4,229,003
Additional Paid in Capital	590,784	597,824
Accumulated Other Comprehensive Income (Loss), Net of Tax	(19,750)	0
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	4,928,669	4,862,053
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	3,709	4,409	16,383		$ 7,370
Prepayments and other current assets	15,041	15,246
Total current assets	18,750	19,655
Investment in subsidiaries	1,427,141	1,431,856
Deferred tax asset - long term	6,764	112
Other Assets	2,843	2,539
Other Assets, Noncurrent	1,436,748	1,434,507
TOTAL ASSETS	1,455,498	1,454,162
Short-term debt	469,313	0
Accumulated deficit	(24,558)	(24,558)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	546,476	573,266	$ 572,276	$ 571,183
Long-term debt	401,415	868,880
Other non-current liabilities	0	0
Accounts payable and accrued expenses	292	326
Accrued Income Taxes, Current	0	243
Accrued interest	11,442	11,444
Accrued and other current liabilities	26,560	3
Total current liabilities	507,607	12,016
Total non-current liabilities	401,415	868,880
Liabilities	909,022	880,896
Additional Paid in Capital	590,784	597,824
Accumulated Other Comprehensive Income (Loss), Net of Tax	(19,750)	0
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$ 1,455,498	$ 1,454,162