Accumulated Other Comprehensive Income (Loss) Changes in AOCI, net of tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	$ (86,437)
Accumulated other comprehensive income (loss), net of tax	(27,432)	$ (86,437)
Subsidiaries [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	(180,956)
Accumulated other comprehensive income (loss), net of tax	(113,141)	(180,956)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	(86,437)	(84,149)	$ (77,202)
Other comprehensive income (loss) before reclassifications	49,226	(9,058)	(7,337)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	9,779	6,770	390
Net current-period other comprehensive income (loss)	59,005	(2,288)	(6,947)
Accumulated other comprehensive income (loss), net of tax	(27,432)	(86,437)	(84,149)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] | Subsidiaries [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	(175,972)	(183,108)	(185,130)
Other comprehensive income (loss) before reclassifications	49,265	(8,717)	(8,096)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	18,166	15,853	10,118
Net current-period other comprehensive income (loss)	67,431	7,136	2,022
Accumulated other comprehensive income (loss), net of tax	(108,541)	(175,972)	(183,108)
Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	(86,437)	(84,149)	(77,202)
Other comprehensive income (loss) before reclassifications	49,226	(9,058)	(7,337)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	9,779	6,770	390
Net current-period other comprehensive income (loss)	59,005	(2,288)	(6,947)
Accumulated other comprehensive income (loss), net of tax	(27,432)	(86,437)	(84,149)
Comprehensive Income [Member] | Subsidiaries [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	(180,956)	(188,477)	(190,884)
Other comprehensive income (loss) before reclassifications	49,265	(8,717)	(8,096)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	18,550	16,238	10,503
Net current-period other comprehensive income (loss)	67,815	7,521	2,407
Accumulated other comprehensive income (loss), net of tax	(113,141)	(180,956)	(188,477)
Interest Rate Swap [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] | Subsidiaries [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), net of tax	(4,984)	(5,369)	(5,754)
Other comprehensive income (loss) before reclassifications	0	0	0
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	384	385	385
Net current-period other comprehensive income (loss)	384	385	385
Accumulated other comprehensive income (loss), net of tax	$ (4,600)	$ (4,984)	$ (5,369)