Loans - Presentation of Recorded Investment in Nonaccrual Loans and Loans Past Due Over 90 Days and Still on Accrual by Class of Loans (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	$ 24,359	$ 44,109
Financing receivable, recorded investment, Loans past due over 90 days and still accruing	3,125	3,678
Permanent Real Estate Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	13,299	30,576
Financing receivable, recorded investment, Loans past due over 90 days and still accruing	3,125	3,678
Permanent Real Estate Loans [Member] | One-to Four-Family Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	6,127	5,437
Financing receivable, recorded investment, Loans past due over 90 days and still accruing
Permanent Real Estate Loans [Member] | Multi-Family Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	705	2,027
Financing receivable, recorded investment, Loans past due over 90 days and still accruing
Permanent Real Estate Loans [Member] | Nonresidential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	5,839	17,065
Financing receivable, recorded investment, Loans past due over 90 days and still accruing	3,125	3,678
Permanent Real Estate Loans [Member] | Land [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	628	6,047
Financing receivable, recorded investment, Loans past due over 90 days and still accruing
Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	3,320	7,466
Financing receivable, recorded investment, Loans past due over 90 days and still accruing
Construction Loans [Member] | One-to Four-Family Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	3,320	7,466
Financing receivable, recorded investment, Loans past due over 90 days and still accruing
Construction Loans [Member] | Multi-Family and Nonresidential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual
Financing receivable, recorded investment, Loans past due over 90 days and still accruing
Consumer Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	3,563	4,842
Financing receivable, recorded investment, Loans past due over 90 days and still accruing
Consumer Loans [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	3,134	3,298
Financing receivable, recorded investment, Loans past due over 90 days and still accruing
Consumer Loans [Member] | Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	100	105
Financing receivable, recorded investment, Loans past due over 90 days and still accruing
Consumer Loans [Member] | Marine [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	140	176
Financing receivable, recorded investment, Loans past due over 90 days and still accruing
Consumer Loans [Member] | Recreational Vehicles [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	184	1,259
Financing receivable, recorded investment, Loans past due over 90 days and still accruing
Consumer Loans [Member] | Others [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	5	4
Financing receivable, recorded investment, Loans past due over 90 days and still accruing
Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	4,177	1,225
Financing receivable, recorded investment, Loans past due over 90 days and still accruing
Commercial Loans [Member] | Secured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	4,036	1,194
Financing receivable, recorded investment, Loans past due over 90 days and still accruing
Commercial Loans [Member] | Unsecured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	141	31
Financing receivable, recorded investment, Loans past due over 90 days and still accruing