Rendering

Component: (Network and Table)
Network
2417402 - Disclosure - Indebtedness (Details)
(http://www.wrberkley.com/role/IndebtednessDetails)
TableSchedule of Long-term Debt Instruments [Table]
Slicers (applies to each fact value in each table cell)
Reporting Entity [Axis]0000011544 (http://www.sec.gov/CIK)
Debt Instrument [Line Items]Period [Axis]
2019-12-31
2017-12-31
2016-12-31
2015-12-31
Long-term Debt, Type [Axis]Long-term Debt, Type [Axis]Long-term Debt, Type [Axis]Long-term Debt, Type [Axis]
Long-term Debt, Type [Domain]Long-term Debt, Type [Domain]Senior NotesSenior Notes and Other DebtJunior Subordinated Debt [Member]Subordinated Debt [Member]Subordinated Debentures Subject to Mandatory Redemption [Member]Long-term Debt, Type [Domain]Senior NotesSenior Notes and Other DebtJunior Subordinated Debt [Member]Subordinated Debentures Subject to Mandatory Redemption [Member]Long-term Debt, Type [Domain]
Debt Instrument [Axis]Debt Instrument [Axis]Debt Instrument [Axis]Debt Instrument [Axis]Debt Instrument [Axis]Debt Instrument [Axis]Debt Instrument [Axis]Debt Instrument [Axis]Debt Instrument [Axis]Debt Instrument [Axis]Debt Instrument [Axis]Debt Instrument [Axis]Debt Instrument [Axis]
Subsidiary DebtSubsidiary DebtSenior Notes due August 15, 2019Senior Notes due September 15, 2019Senior Notes due September 15, 2020Senior Notes due January 1, 2022Senior Notes due March 15, 2022Senior Notes due February 15, 2037Senior Notes due August 1, 2044 [Member]Debt Instrument, Name [Domain]Five Point Six Two Five Percent Subordinated Debentures [Member]Five Point Nine Percent Subordinated Debentures [Domain]Five Point Eight Percent Subordinated Debentures [Member] [Domain]Debt Instrument, Name [Domain]SubordinatedDebenturedueApril30,2053 [Member]SubordinatedDebenturedueMarch1,2056 [Member] [Member]Subordinated Debenture due June1, 2056 [Member]Debt Instrument, Name [Domain]Debt Instrument, Name [Domain]Subsidiary DebtSenior Notes due August 15, 2019Senior Notes due September 15, 2019Senior Notes due September 15, 2020Senior Notes due January 1, 2022Senior Notes due March 15, 2022Senior Notes due February 15, 2037Senior Notes due August 1, 2044 [Member]Debt Instrument, Name [Domain]Debt Instrument, Name [Domain]Debt Instrument, Name [Domain]Subsidiary Debt
Rate
  
6.15%  
7.375%  
5.375%  
8.70%  
4.625%  
6.25%  
4.75%  
 
5.625%  
5.90%  
5.75%  
                  
Aggregate Indebtedness
             
290,000,000  
              
0  
  
Face Value
  
140,651,000  
300,000,000  
300,000,000  
76,503,000  
350,000,000  
250,000,000  
350,000,000  
1,772,708,000  
   
110,000,000  
   
350,000,000  
750,000,000  
5,554,000  
        
0  
340,320,000  
 
Carrying Value
  
140,301,000  
299,308,000  
298,747,000  
76,151,000  
347,834,000  
247,786,000  
344,914,000  
1,760,595,000  
   
727,630,000  
340,579,000  
105,952,000  
281,099,000  
  
5,554,000 1
149,484,000  
299,054,000  
298,411,000  
76,097,000  
347,417,000  
247,676,000  
344,730,000  
1,844,621,000  
340,320,000  
 
81,752,000 1
Repayments in 2014
                               
Repayments in 2015
2,000,000  
4,000,000  
                             
Repayments in 2016
                               
Repayments thereafter
                               
1: Subsidiary debt is due as follows: $4 million in 2017