Contingent Liabilities - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended
	Dec. 31, 2013 complaint member	Dec. 31, 2013 member
Loss Contingencies [Line Items]
Number of plaintiffs		36
Pending Litigation [Member]
Loss Contingencies [Line Items]
Number of new complaints	3
Number of former members of McGrogan class	34	34
Specified average age of plaintiffs		62 years
Ira Market Rate For Savings Account [Member] | Pending Litigation [Member]
Loss Contingencies [Line Items]
Market rate savings balance	$ 4	$ 4
Minimum [Member] | Unasserted Claim [Member]
Loss Contingencies [Line Items]
Number of Customer Affected	700	700
Maximum [Member] | Unasserted Claim [Member]
Loss Contingencies [Line Items]
Number of Customer Affected	900	900
McGrogan Class Action [Member] | Ira Market Rate For Savings Account [Member] | Pending Litigation [Member]
Loss Contingencies [Line Items]
Interest rate on deposits		3.50%
McGrogan Class Action [Member] | Minimum [Member] | Ira Market Rate For Savings Account [Member] | Pending Litigation [Member]
Loss Contingencies [Line Items]
Interest rate on deposits		8.00%
Jarrett [Member] | Pending Litigation [Member]
Loss Contingencies [Line Items]
Number of plaintiffs		8
Young [Member] | Pending Litigation [Member]
Loss Contingencies [Line Items]
Number of plaintiffs		12
Fisanik [Member] | Pending Litigation [Member]
Loss Contingencies [Line Items]
Number of plaintiffs		14
Other Liabilities [Member] | Unasserted Claim [Member]
Loss Contingencies [Line Items]
Loss Contingency Accrual, Carrying Value, Period Increase (Decrease)		$ 0.8