Condensed Consolidated Statements Of Retained Earnings (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Condensed Consolidated Statements Of Retained Earnings [Abstract]
Balance at the beginning of the period	$ 1,239,135	$ 1,158,501
Net income	3,940	42,893
Subtotal	1,243,075	1,201,394
Dividends declared:
Common stock dividends declared to Parent	57,100	50,000
Preferred stock dividends declared	490	490
Subtotal	57,590	50,490
Balance at the end of the period	$ 1,185,485	$ 1,150,904