Segment Information (Entity-Wide Disclosures) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Customer revenues	$ 403,351	$ 366,073	$ 334,576	$ 348,183	$ 280,779	$ 204,919	$ 203,607	$ 203,040	$ 1,452,183	$ 892,345	$ 1,068,200
Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues									1,452,183	892,345	1,068,200
CAM [Member]
Segment Reporting Information [Line Items]
Customer revenues									285,276	228,956	209,213
CAM [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues										156,516	140,434
All other [Member]
Segment Reporting Information [Line Items]
Customer revenues									$ 314,014	286,579	433,208
All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues										$ 187,025	$ 313,045