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	$ 393,393		$ 376,138	$ 350,054
Level 3
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	30,104		31,670	36,106
Net realized gains (losses)	2,308		2,664	838
Net unrealized gains (losses)	420		(2,751)	3,211
Purchases, issuances and settlements, net	726		(1,479)	(8,485)
Transfers in (out) of Level 3	(9,581)	[1]	0	0
Fair value of plan assets at Dec. 31	23,977		30,104	31,670
Asset-backed securities
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Dec. 31	889		1,755	4,018
Asset-backed securities | Level 3
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	1,755		4,018	3,450
Net realized gains (losses)	0		531	328
Net unrealized gains (losses)	0		(741)	(355)
Purchases, issuances and settlements, net	0		(2,053)	595
Transfers in (out) of Level 3	(1,755)	[1]	0	0
Fair value of plan assets at Dec. 31	0		1,755	4,018
Mortgage-backed securities
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Dec. 31	1,939		4,331	7,907
Mortgage-backed securities | Level 3
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	4,331		7,907	11,060
Net realized gains (losses)	0		245	170
Net unrealized gains (losses)	0		(265)	(865)
Purchases, issuances and settlements, net	0		(3,556)	(2,458)
Transfers in (out) of Level 3	(4,331)	[1]	0	0
Fair value of plan assets at Dec. 31	0		4,331	7,907
Private equity investments
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Dec. 31	18,222		17,049	16,159
Private equity investments | Level 3
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	17,049		16,159	11,464
Net realized gains (losses)	2,630		1,886	401
Net unrealized gains (losses)	(1,055)		(2,296)	1,300
Purchases, issuances and settlements, net	(402)		1,300	2,994
Transfers in (out) of Level 3	0	[1]	0	0
Fair value of plan assets at Dec. 31	18,222		17,049	16,159
Real estate
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Dec. 31	5,755		6,969	3,586
Real estate | Level 3
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	6,969		3,586	10,132
Net realized gains (losses)	(322)		2	(61)
Net unrealized gains (losses)	1,475		551	3,131
Purchases, issuances and settlements, net	1,128		2,830	(9,616)
Transfers in (out) of Level 3	(3,495)	[1]	0	0
Fair value of plan assets at Dec. 31	$ 5,755		$ 6,969	$ 3,586

[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.