XML 54 R41.htm IDEA: XBRL DOCUMENT v3.7.0.1

Investments (Other Investments) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Other Investments
Other investments	$ 80,576	$ 81,892
Investments in LPs/LLCs, at cost [Member]
Other Investments
Other investments	47,164	46,852
Convertible securities, at fair value [Member]
Other Investments
Other investments	29,978	31,501
Other, principally FHLB capital stock at cost [Member]
Other Investments
Other investments	$ 3,434	$ 3,539

X

- Definition

Amount of investments classified as other.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1(f,g))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

Name:	us-gaap_OtherInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- References

No definition available.

+ Details

Name:	us-gaap_OtherInvestmentsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_InvestmentTypeAxis=pra_PrivateEquityFundsValuedAtCostMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_ConvertibleDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=pra_FHLBAndOtherInvestmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: