Segment Information (Financial Information) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Segment Reporting Information [Line Items]
Operating Revenues	$ 436,727	$ 375,571	$ 1,174,733	$ 1,088,032
Depreciation and Amortization	43,610	42,389	130,639	132,767
Operating Income/(Loss)	73,183	61,867	210,587	71,670
Equity in Earnings/(Losses) of Affiliates, Net of Tax	971	607	1,859	498
Net Income/(Loss) From Continuing Operations	102,467	31,668	177,820	8,225
Capital Expenditures	25,091	26,414	68,904	78,652
Assets	4,185,679		4,185,679		$ 3,957,295
Operating Segments | PIRM
Segment Reporting Information [Line Items]
Operating Revenues	176,248	169,079	504,379	501,854
Depreciation and Amortization	23,474	23,061	69,833	72,135
Operating Income/(Loss)	22,670	18,375	65,249	44,110
Equity in Earnings/(Losses) of Affiliates, Net of Tax	1,013	762	2,483	720
Net Income/(Loss) From Continuing Operations	58,325	19,366	102,451	38,382
Capital Expenditures	16,957	10,706	42,813	36,767
Assets	1,851,655		1,851,655		1,932,643
Operating Segments | UWS
Segment Reporting Information [Line Items]
Operating Revenues	263,342	209,138	680,455	593,175
Depreciation and Amortization	12,017	11,800	36,091	39,391
Operating Income/(Loss)	124,699	70,831	281,567	121,946
Equity in Earnings/(Losses) of Affiliates, Net of Tax	0	(4)	0	(12)
Net Income/(Loss) From Continuing Operations	124,834	70,642	281,717	121,745
Capital Expenditures	2,366	1,942	5,891	8,472
Assets	2,019,299		2,019,299		2,008,233
Corporate
Segment Reporting Information [Line Items]
Operating Revenues	0	0	0	0
Depreciation and Amortization	8,119	7,528	24,715	21,241
Operating Income/(Loss)	(74,186)	(27,339)	(136,229)	(94,386)
Equity in Earnings/(Losses) of Affiliates, Net of Tax	(42)	(151)	(624)	(210)
Net Income/(Loss) From Continuing Operations	(80,692)	(58,340)	(206,348)	(151,902)
Capital Expenditures	5,768	13,766	20,200	33,413
Assets	6,185,679		6,185,679		5,950,472
Eliminations
Segment Reporting Information [Line Items]
Operating Revenues	(2,863)	(2,646)	(10,101)	(6,997)
Depreciation and Amortization	0	0	0	0
Operating Income/(Loss)	0	0	0	0
Equity in Earnings/(Losses) of Affiliates, Net of Tax	0	0	0	0
Net Income/(Loss) From Continuing Operations	0	0	0	0
Capital Expenditures	0	$ 0	0	$ 0
Assets	$ (5,870,954)		$ (5,870,954)		$ (5,934,053)