Loans - Loans by Class Modified as Troubled Debt Restructurings with Payment Default (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014 SecurityLoan	Dec. 31, 2013 SecurityLoan
Financing Receivable Recorded Investment [Line Items]
Number of loans	3	16
Recorded Investment	$ 272	$ 2,540
Permanent Real Estate Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Number of loans	1	7
Recorded Investment	145	1,526
Permanent Real Estate Loans [Member] | Land [Member]
Financing Receivable Recorded Investment [Line Items]
Number of loans		2
Recorded Investment		487
Permanent Real Estate Loans [Member] | One-to Four-Family Residential [Member]
Financing Receivable Recorded Investment [Line Items]
Number of loans	1	4
Recorded Investment	145	576
Permanent Real Estate Loans [Member] | Multi-Family Residential [Member]
Financing Receivable Recorded Investment [Line Items]
Number of loans		1
Recorded Investment		463
Construction Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Number of loans		1
Recorded Investment		623
Construction Loans [Member] | One-to Four-Family Residential [Member]
Financing Receivable Recorded Investment [Line Items]
Number of loans		1
Recorded Investment		623
Consumer Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Number of loans	2	8
Recorded Investment	127	391
Consumer Loans [Member] | Home Equity [Member]
Financing Receivable Recorded Investment [Line Items]
Number of loans	2	6
Recorded Investment	127	207
Consumer Loans [Member] | Recreational Vehicles [Member]
Financing Receivable Recorded Investment [Line Items]
Number of loans		2
Recorded Investment		$ 184