Senior and Subordinated Debt - Senior Debt (Parenthetical) (Detail) (7.125% Senior Notes [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2010	May 09, 2005	Apr. 01, 2005
7.125% Senior Notes [Member]
Debt Instrument [Line Items]
Senior Notes repurchased	$ 10,000
Senior Notes repurchased interest rate	7.125%
Repurchased Senior Notes at cost, excluding accrued interest	10,375
Unamortized debt issuance costs	49
Pre-tax gain or loss from issuance of senior notes	424
Interest rate forward agreement deemed to be effective portion of the hedge		$ 11,003
Duration of time amortized as charge to interest expense, in years			10 years