Changes and Reclassifications Out of Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Mar. 31, 2013	Dec. 31, 2012
Total Reclassifications Out of OCI Current Period [Roll Forward]
Other Comprehensive Income (Loss), Arising During Period, Net of Tax	$ (49,593)	$ 4,103	$ (57,513)	$ 5,987
Accumulated Other Comprehensive Reclass Amounts During Period-Total	1,815		1,821
Accumulated other comprehensive loss	(71,897)	(18,425)	(71,897)	(18,425)	(24,119)	(16,205)
Unrealized securities gains and losses
Total Reclassifications Out of OCI Current Period [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(274)		(274)		47,504	55,418
Other Comprehensive Income (Loss), Arising During Period, Net of Tax	(49,593)		(57,513)
Accumulated Other Comprehensive Reclass Amounts During Period-Total	1,815		1,821
Pension and post- retirement costs
Total Reclassifications Out of OCI Current Period [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax	(71,623)		(71,623)		(71,623)	(71,623)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Net of Tax	$ 0		$ 0