Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Fixed maturities, amortized cost	$ 9,038,158	$ 9,929,137
Equity securities, cost	2,208,834	1,951,658
Senior long-term debt and other debt, estimated fair value	$ 2,403,000	$ 2,493,000