Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013 Payment Employees
Commitments And Contingencies Disclosure [Abstract]
Outstanding loan commitments and approvals to fund loans	$ 20.9
Prime-based loans	$ 18.1
Lease expiration date of office space in Dallas, Texas	Feb. 01, 2015
Employment agreements with executive officer expiration date	Dec. 31, 2015
Severance compensation paid in terms of annual compensation	2.99 times the average of the last three years
Death payments in terms of annual salary paid	2
Disability payments in terms of annual salary paid	1
Number of employees covered under employee agreement	2
Employment agreement term	3 years