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Comprehensive Income (Components of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2017 | Sep. 30, 2016 | Sep. 30, 2017 | Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance, December 31, 2016 |  |  | $ (15,950) |
Amounts reclassified into net income: Non-credit OTTI | $ 25 | $ 0 | 25 | $ 0
Amounts reclassified from AOCI, HTM related | (35) | (9) | (95) | (68)
Amounts reclassified from AOCI, All Other | (4,394) | (2,395) | (4,638) | (1,786)
OCI before reclassifications, Defined Benefit Pension and Post Retirement Plans |  |  | 0 |
Amount reclassified into net income: Net actuarial loss | 329 | 1,050 | 989 | 3,021
Other comprehensive income | 6,818 | (9,798) | 47,265 | 71,634
Other Comprehensive Income, Defined Benefit Pension and Post Retirement Plans, Adjustment, Net of Tax | 329 | $ 1,050 | 989 | 3,021
Ending Balance, September 30, 2017 | 31,315 |  | 31,315 |
Available-for-sale Securities [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance, December 31, 2016 |  |  | 42,170 |
OCI before reclassifications |  |  | 50,961 |
Other comprehensive income |  |  | 46,323 |
Ending Balance, September 30, 2017 | 88,493 |  | 88,493 |
Investments [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance, December 31, 2016 |  |  | 42,122 |
OCI before reclassifications |  |  | 50,984 |
Amounts reclassified from AOCI |  |  | (4,708) |
Other comprehensive income |  |  | 46,276 |
Ending Balance, September 30, 2017 | 88,398 |  | 88,398 |
Accumulated Other-than-Temporary Impairment [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance, December 31, 2016 |  |  | (150) |
OCI before reclassifications |  |  | 23 |
Other comprehensive income |  |  | 48 |
Ending Balance, September 30, 2017 | (102) |  | (102) |
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Held-to-maturity Securities [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance, December 31, 2016 |  |  | 102 |
OCI before reclassifications |  |  | 0 |
Other comprehensive income |  |  | (95) |
Ending Balance, September 30, 2017 | 7 |  | 7 |
Accumulated Defined Benefit Plans Adjustment [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance, December 31, 2016 |  |  | (58,072) |
Amount reclassified into net income: Net actuarial loss |  |  | 989 |
Ending Balance, September 30, 2017 | (57,083) |  | (57,083) |
Accumulated other comprehensive income (loss) [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance, December 31, 2016 |  |  | (15,950) |
OCI before reclassifications |  |  | 50,984 |
Amounts reclassified from AOCI |  |  | (3,719) |
Other comprehensive income |  |  | 47,265 | $ 71,634
Ending Balance, September 30, 2017 | $ 31,315 |  | $ 31,315 |

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- Definition Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e637-108580 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e681-108580 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669686-108580 + Details
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