Repurchase Reserves for Previously Sold Loans (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
Jun. 30, 2013	Dec. 31, 2012
Mortgage Banking [Abstract]
Beginning balance	$ 906	$ 115
Provision for repurchases	83	791
Settlements
Total repurchases reserve	$ 989	$ 906

Cash Payment Upon Settlement Of Repurchase Agreement

No definition available.

Name:	pmbc_CashPaymentUponSettlementOfRepurchaseAgreement
Namespace Prefix:	pmbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration