Stock-Based Compensation Plans - Summary of Activity Related to Company's Restricted Stock (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
Sep. 30, 2014	Sep. 30, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Total value of the restricted share grants	$ 2,566	$ 3,271

Share based compensation arrangement by share based payment award equity instruments other than options granted in period fair value.

No definition available.

Name:	pps_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantedInPeriodFairValue
Namespace Prefix:	pps_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration