Loans Receivable and Allowance for Loan Losses - Aging of Loans and Accrual Status (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment, Past Due
Total Past Due	$ 2,907	$ 2,984
Loans Not Past Due	1,258,708	1,187,831
Total ending loan balance	1,261,615	1,190,815
Nonaccrual Loans	5,058	5,415
One- to four-family residential
Financing Receivable, Recorded Investment, Past Due
Total Past Due	2,829	2,969
Loans Not Past Due	1,203,280	1,138,966
Total ending loan balance	1,206,109	1,141,935
Nonaccrual Loans	4,895	5,282
Multi-family residential
Financing Receivable, Recorded Investment, Past Due
Loans Not Past Due	9,678	9,810
Total ending loan balance	9,678	9,810
Construction, Commercial and Other Mortgage Loans
Financing Receivable, Recorded Investment, Past Due
Loans Not Past Due	25,335	19,175
Total ending loan balance	25,335	19,175
Home Equity Loans and Lines of Credit
Financing Receivable, Recorded Investment, Past Due
Total Past Due	77
Loans Not Past Due	16,007	15,340
Total ending loan balance	16,084	15,340
Nonaccrual Loans	163	124
Loans on deposit accounts
Financing Receivable, Recorded Investment, Past Due
Loans Not Past Due	310	304
Total ending loan balance	310	304
Consumer and other loans
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1	15
Loans Not Past Due	4,098	4,236
Total ending loan balance	4,099	4,251
Nonaccrual Loans		9
30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	127	1,358
30 - 59 Days Past Due | One- to four-family residential
Financing Receivable, Recorded Investment, Past Due
Total Past Due	91	1,354
30 - 59 Days Past Due | Home Equity Loans and Lines of Credit
Financing Receivable, Recorded Investment, Past Due
Total Past Due	35
30 - 59 Days Past Due | Consumer and other loans
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1	4
60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	945	1
60 - 89 Days Past Due | One- to four-family residential
Financing Receivable, Recorded Investment, Past Due
Total Past Due	945
60 - 89 Days Past Due | Consumer and other loans
Financing Receivable, Recorded Investment, Past Due
Total Past Due		1
90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1,835	1,625
90 Days or Greater Past Due | One- to four-family residential
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1,793	1,615
90 Days or Greater Past Due | Home Equity Loans and Lines of Credit
Financing Receivable, Recorded Investment, Past Due
Total Past Due	$ 42
90 Days or Greater Past Due | Consumer and other loans
Financing Receivable, Recorded Investment, Past Due
Total Past Due		$ 10