Employee Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Defined Benefit Postretirement Health Coverage [Member] | Employees Retired before January 1, 1993 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Defined Benefit Plan, Maximum Coverage per Retiree			100.00%
Pension Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Defined Benefit Plan, Benefit Obligation	$ 14,841		$ 14,841		$ 17,306
Defined Benefit Plan, Benefit Obligation, Before Settlements	15,468		15,468
Defined Benefit Plan, Settlements, Benefit Obligation			(627)
Defined Benefit Plan, Fair Value of Plan Assets	10,677		10,677		10,019
Defined Benefit Plan, Fair Value of Plan Assets, Before Settlements	11,304		11,304
Defined Benefit Plan, Settlements, Plan Assets			(627)
Defined Benefit Plan, Funded Status of Plan	(4,164)		(4,164)		(7,287)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax	6,184		6,184		9,630
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax, before Settlements	6,448		6,448
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.20%		4.20%		3.30%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets			7.50%		7.50%
Components of net periodic benefit costs:
Interest cost	133	148	399	452
Expected return on plan assets	(164)	(182)	(494)	(574)
Defined Benefit Plan, Amortization of Net Gains (Losses)	51	41	154	120
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements	(264)	0	(264)	(353)
Net periodic benefit cost	284	7	323	351
Other Postretirement Benefit Plans, Defined Benefit [Member]
Components of net periodic benefit costs:
Interest cost	1	2	4	7
Defined Benefit Plan, Amortization of Net Gains (Losses)	(1)	0	(5)	(1)
Net periodic benefit cost	$ 0	$ 2	$ (1)	$ 6
Other Postretirement Benefit Plans, Defined Benefit [Member] | Employees Hired before January 1, 2003 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Defined Benefit Plan, Contribution Per Employee, Coverage Basis, Consecutive Period of Highest Average Monthly Compensation			5 years
Defined Benefit Plan, Contribution Per Employee, Coverage Basis, Lastest Service Period			10 years
Other Postretirement Benefit Plans, Defined Benefit [Member] | Employees Hired on or after January 1, 2003 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Defined Benefit Plan, Annual Contribution Per Employee, Percent			2.00%