Stock Compensation Plans - Summary of Plan Activity (Detail) - $ / shares	Jul. 01, 2018	Jan. 01, 2018	Jul. 01, 2017	Jan. 01, 2017	Jul. 01, 2016	Jan. 01, 2016
Issue Date One [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares Issued, Price						$ 11.97
Shares Issued, Shares						18,387
Issue Date Two [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares Issued, Price					$ 11.83
Shares Issued, Shares					22,418
Issue Date Three [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares Issued, Price				$ 13.76
Shares Issued, Shares				18,512
Issue Date Four [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares Issued, Price			$ 13.52
Shares Issued, Shares			25,155
Issue Date Five [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares Issued, Price		$ 13.34
Shares Issued, Shares		20,662
Issue Date Six [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares Issued, Price	$ 11.57
Shares Issued, Shares	27,802