Fair Value Measurements - Information about Valuation Inputs for Fixed Income Securities Classified as Level 3 (Detail) (Successor [Member])	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Corporate Obligations [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Coupon rate	0.345%
Fair Value Inputs Maturity	19 years 1 month 21 days
Yield	4.93%
Variable Interest Entity, Primary Beneficiary [Member] | United States Transactions [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Coupon rate	5.88%	5.88%
Fair Value Inputs Maturity	15 years 8 months 20 days	15 years 10 months 4 days
Yield	7.50%	7.37%
Variable Interest Entity, Primary Beneficiary [Member] | European Transactions [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Coupon rate	0.57%	0.30%
Fair Value Inputs Maturity	17 years 11 months	21 years 2 months 30 days
Yield	7.30%	9.52%