Benefit Plans and Other Postretirement Benefits, Changes in Level 3 Pension Plan Assets (Details) (Pension Plans, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Dec. 31	$ 136,935		$ 136,546	$ 121,348
Level 3
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	14,894		15,807	17,801
Net realized gains (losses)	954		1,236	352
Net unrealized gains (losses)	(1,713)		(1,254)	1,230
Purchases, issuances and settlements, net	284		(895)	(3,576)
Transfers in (out) of Level 3	(4,618)	[1]	0	0
Fair value of plan assets at Dec. 31	9,801		14,894	15,807
Asset-backed securities
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Dec. 31	307		749
Asset-backed securities | Level 3
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	749		1,578	1,367
Net realized gains (losses)	0		197	121
Net unrealized gains (losses)	0		(273)	(125)
Purchases, issuances and settlements, net	0		(753)	215
Transfers in (out) of Level 3	(749)	[1]	0	0
Fair value of plan assets at Dec. 31	0		749	1,578
Mortgage-backed securities
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Dec. 31	684		2,128
Mortgage-backed securities | Level 3
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	2,128		3,781	5,984
Net realized gains (losses)	0		93	55
Net unrealized gains (losses)	0		(112)	(295)
Purchases, issuances and settlements, net	0		(1,634)	(1,963)
Transfers in (out) of Level 3	(2,128)	[1]	0	0
Fair value of plan assets at Dec. 31	0		2,128	3,781
Private equity investments
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Dec. 31	7,502		8,545
Private equity investments | Level 3
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	8,545		8,440	6,704
Net realized gains (losses)	1,083		945	210
Net unrealized gains (losses)	(1,960)		(1,197)	648
Purchases, issuances and settlements, net	(166)		357	878
Transfers in (out) of Level 3	0	[1]	0	0
Fair value of plan assets at Dec. 31	7,502		8,545	8,440
Real estate
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Dec. 31	2,299		3,472
Real estate | Level 3
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	3,472		2,008	3,746
Net realized gains (losses)	(129)		1	(34)
Net unrealized gains (losses)	247		328	1,002
Purchases, issuances and settlements, net	450		1,135	(2,706)
Transfers in (out) of Level 3	(1,741)	[1]	0	0
Fair value of plan assets at Dec. 31	$ 2,299		$ 3,472	$ 2,008

[1] Transfers out of Level 3 into Level 2 were principally due to diminished use of unobservable inputs that were previously significant to these fair value measurements and were subsequently sold during 2013.