Investments Equity Investments (Details) - Successor [Member] - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Other investments	$ 452,032	$ 450,307
Real Estate [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	33,218	33,303
Hedge Funds, Multi-strategy [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	49,292	53,985
Interest Rate Contract [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	223,364	261,315
Illiquid Investments [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	63,027	39,068
Insurance Linked [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	13,224	0
Equity [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	36,489	32,633
Equity investments in pooled funds [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	418,614	420,304
Readily determinable fair value [Member] | Interest Rate Contract [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	$ 52,264	$ 51,158