SCHEDULE VI - Supplemental Information Concerning Property-Casualty Insurance Operations (Details) (Consolidated subsidiaries [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Consolidated subsidiaries [Member]
Supplemental Information Concerning Property-Casualty Insurance Operations [Line Items]
Deferred policy acquisition costs	$ 434,111	$ 363,188	$ 339,094
Liability for unpaid losses and loss expenses	10,646,318	10,709,371	11,273,091
Unearned premiums	1,699,430	1,517,358	1,433,525
Premiums earned	4,241,064	3,691,341	3,855,606
Losses and loss expenses incurred	2,397,256	2,157,629	3,722,309
Amortization of deferred policy acquisition costs	952,997	821,022	821,477
Paid losses and loss expenses	2,401,559	2,705,062	2,990,559
Premiums written	$ 4,432,829	$ 3,774,474	$ 3,700,575