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Business Combinations (Narrative) (Details) - USD ($) $ in Thousands |  |  | 12 Months Ended
--- | --- | --- | ---
Jan. 01, 2014 | Jan. 01, 2013 | Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Business Acquisition [Line Items] |  |  |  |  |
Gain on acquisition |  |  | $ 0 | $ 0 | $ 32,314
Eastern Insurance Holdings [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Voting interests acquired | 100.00% |  |  |  |
Total purchase consideration | $ 205,000 |  |  |  |
Expenses related to the purchase of business |  |  |  | 2,200 | 900
Revenue of aquiree since acquisition date |  |  |  | 202,200 |
Earnings of acquiree since acquisition date |  |  |  | $ 9,100 |
Medmarc [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Total purchase consideration |  | $ 153,700 |  |  |
Expenses related to the purchase of business |  |  |  |  | 2,600
Gain on acquisition |  |  |  |  | $ 32,300
Business acquisition, related premium credits to eligible policyholders |  | $ 7,500 |  |  |

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- Definition Percentage of voting equity interests acquired at the acquisition date in the business combination. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=56956515&loc=d3e1392-128463 + Details
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- Definition This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 25 -Paragraph 23 -URI http://asc.fasb.org/extlink&oid=34752592&loc=d3e1043-128460 + Details
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- Definition In a business combination in which the amount of net identifiable assets acquired and liabilities assumed exceeds the aggregate consideration transferred or to be transferred (as defined), this element represents the amount of gain recognized by the entity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 25 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6911189&loc=d3e6393-128476 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6527-128477 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (f)(1) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6571-128477 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 25 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6911189&loc=d3e6387-128476 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 25 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6911189&loc=d3e6396-128476 + Details
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- Definition Fair value at acquisition-date of the assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interests issued by the acquirer, including but not limited to, instruments or interests issued or issuable in consideration for the business combination. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=56956515&loc=d3e1392-128463 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 + Details
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