Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2013
Statement of Stockholders' Equity [Abstract]
Cash dividend per share	$ 0.742us-gaap_DividendsPayableAmountPerShare	$ 0.80us-gaap_DividendsPayableAmountPerShare	$ 0.78us-gaap_DividendsPayableAmountPerShare
Percentage of stock dividend	5.00%psbq_StockDividendRatePercentage

The per share amount of a dividend declared, but not paid, as of the financial reporting date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

Name:	us-gaap_DividendsPayableAmountPerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant