Pension Plan and Employee Benefits Pension Plan and Employee Benefits, 401 (K) Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
401(k) Plan [Abstract]
401 (k) Plan expense	$ 1,493	$ 1,201
Other Subsidiaries [Member]
401(k) Plan [Abstract]
401 (k) Plan expense	$ 400	$ 300