Consolidated Balance Sheets (Parenthetical) - Successor [Member] - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Fixed income securities, amortized cost	$ 5,165,245	$ 5,435,385
Fixed income securities pledged as collateral, amortized cost	64,944	64,833
Short-term investments, amortized cost	504,093	430,827
Other Investments at Fair Value	419,614	420,304
Other investments	$ 452,032	$ 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
Common stock, shares issued	45,275,982	45,194,954
Common stock, shares outstanding	45,275,982	45,194,954
Treasury stock, shares	24,816	22,458