Bank subsidiary (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Noninterest expense
Income before income taxes	$ 52,814	$ 60,087
Income taxes	18,662	21,298
Net income	34,152	38,789
American Savings Bank (ASB)
Interest income
Interest and fees on loans	42,603	44,888
Interest on investment and mortgage-related securities	3,464	3,805
Total interest income	46,067	48,693
Interest expense
Interest on deposit liabilities	1,312	1,779
Interest on other borrowings	1,164	1,261
Total interest expense	2,476	3,040
Net interest income	43,591	45,653
Provision for loan losses	1,858	3,546
Net interest income after provision for loan losses	41,733	42,107
Noninterest income
Fees from other financial services	7,643	7,337
Fee income on deposit liabilities	4,314	4,278
Fee income on other financial products	1,794	1,549
Gain on sale of loans	3,346	2,035
Other income, net	1,592	1,360
Total noninterest income	18,689	16,559
Noninterest expense
Compensation and employee benefits	20,088	18,646
Occupancy	4,123	4,225
Data processing	2,987	2,111
Services	2,103	1,783
Equipment	1,774	1,730
Other expense	7,595	6,707
Total noninterest expense	38,670	35,202
Income before income taxes	21,752	23,464
Income taxes	7,597	7,587
Net income	$ 14,155	$ 15,877