Basis of Presentation (Other Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
SPC dividends payable	$ 47,122	$ 46,925
Unpaid dividends	16,616	267,292	$ 16,516
All other	144,128	123,383
Total other liabilities	$ 207,866	$ 437,600