Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Successor [Member]
Fixed income securities, amortized cost	$ 4,614,623	$ 5,435,385
Fixed income securities pledged as collateral, amortized cost	99,719	64,833
Short-term investments, amortized cost	557,476	430,827
Other Investments	$ 431,630	$ 450,307
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred stock, shares issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	130,000,000	130,000,000
Equity investments in pooled funds [Member] | Successor [Member]
Other Investments at Fair Value	$ 396,689
Other Investments	$ 366,939	$ 420,304