Reserve for Repurchased Loans and Loss Sharing Obligations - Analysis of Reserve for Repurchased Loans and Loss Sharing Obligations (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Disclosure Reserve For Repurchased Loans Analysis Of Reserve For Repurchased Loans [Abstract]
Balance at beginning of year	$ 1,468,000	$ 1,203,000	$ 705,000
Provision charged to operations		975,000	750,000
Loss on loans repurchased, settlements or payments under loss sharing arrangements	(436,000)	(915,000)	(252,000)
Recoveries		205,000
Balance at end of year	$ 1,032,000	$ 1,468,000	$ 1,203,000