Bank subsidiary (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Interest expense
Interest on deposit liabilities	$ 8,983	$ 14,696	$ 34,046
Total interest expense	96,575	101,887	119,873
Provision for loan losses	(15,009)	(20,894)	(32,000)
Noninterest expense
Income before income taxes	216,052	183,247	128,824
Income taxes	75,932	67,822	43,923
Net income	140,120	115,425	84,901
American Savings Bank (ASB)
Interest and dividend income
Interest and fees on loans	184,485	195,192	217,838
Interest and dividends on investment and mortgage-related securities	14,568	14,946	26,977
Total interest and dividend income	199,053	210,138	244,815
Interest expense
Interest on deposit liabilities	8,983	14,696	34,046
Interest on other borrowings	5,486	5,653	9,497
Total interest expense	14,469	20,349	43,543
Net interest income	184,584	189,789	201,272
Provision for loan losses	15,009	20,894	32,000
Net interest income after provision for loan losses	169,575	168,895	169,272
Noninterest income
Fee income on deposit liabilities	18,026	26,369	30,713
Fees from other financial services	28,881	27,280	25,267
Fee income on other financial products	6,704	6,487	5,833
Net gains (losses) on sale of securities	371		(32,034)
Net losses on available-for-sale securities			(15,444)
Other-than-temporary impairment losses			32,167
Net of non-credit losses recognized in other comprehensive income			16,723
Other income	11,372	12,419	15,569
Total noninterest income	65,354	72,555	29,904
Noninterest expense
Compensation and employee benefits	71,137	71,476	73,990
Occupancy	17,154	16,548	22,057
Data processing	8,155	13,213	14,382
Services	7,396	6,594	11,189
Equipment	6,903	6,620	8,849
Office supplies, printing and Postage	3,934	3,928	3,758
Marketing	3,001	2,418	2,134
Communication	1,764	2,221	2,446
Loss on early extinguishment of debt			760
Other expense	23,949	25,920	27,906
Total noninterest expense	143,393	148,938	167,471
Income before income taxes	91,536	92,512	31,705
Income taxes	31,693	34,056	9,938
Net income	$ 59,843	$ 58,456	$ 21,767