Basis of Financial Statement Presentation - Additional Information (Detail) |
9 Months Ended |
---|---|
Sep. 30, 2016
Segment
| |
Basis Of Presentation [Line Items] | |
Number of reportable segments | 1 |
Century Bancorp Capital Trust II [Member] | |
Basis Of Presentation [Line Items] | |
Equity ownership interest | 100.00% |