Supplemental Disclosures of Cash Flow Information - Summary of Noncash Transactions (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Other Significant Noncash Transactions [Line Items]
Stock-based compensation not involving cash	$ 25,642	$ 21,605	$ 14,954
Commitments for low-income housing interests	42,525	29,759	36,722
Capitalized investment income	806	1,537	5,321
Debt assumed to acquire Family Heritage	0	20,000	0
Parent Company [Member]
Other Significant Noncash Transactions [Line Items]
Stock-based compensation not involving cash	25,642	21,605	14,954
Debt assumed to acquire Family Heritage	$ 0	$ 20,000	$ 0