Fair value measurements (Details 2) (USD $)	Sep. 30, 2013		Dec. 31, 2012
Financial liabilities
Short-term borrowings-other than bank	$ 131,341,000		$ 83,693,000
Other bank borrowings	239,612,000		195,926,000
Level 2
Financial assets
Derivative assets	558,000	[1]
Carrying or notional amount
Financial assets
Money market funds	10,000		10,000
Available-for-sale investment and mortgage-related securities	535,264,000		671,358,000
Investment in stock of Federal Home Loan Bank of Seattle	93,413,000		96,022,000
Loans receivable, net	4,010,961,000		3,763,238,000
Derivative assets	24,196,000
Financial liabilities
Deposit liabilities	4,310,842,000		4,229,916,000
Short-term borrowings-other than bank	131,341,000		83,693,000
Other bank borrowings	239,612,000		195,926,000
Long-term debt, net-other than bank	1,422,880,000		1,422,872,000
Derivative liabilities	22,185,000
Carrying or notional amount | American Savings Bank (ASB)
Financial liabilities
Loan commitments and unused lines and letters of credit	1,600,000,000		1,500,000,000
Notional amount of loans serviced	1,400,000,000		1,300,000,000
Estimated fair value
Financial assets
Money market funds	10,000		10,000
Available-for-sale investment and mortgage-related securities	535,264,000		671,358,000
Investment in stock of Federal Home Loan Bank of Seattle	93,413,000		96,022,000
Loans receivable, net	4,149,137,000		3,957,752,000
Derivative assets	558,000
Financial liabilities
Deposit liabilities	4,313,560,000		4,235,527,000
Short-term borrowings-other than bank	131,341,000		83,693,000
Other bank borrowings	252,230,000		212,163,000
Long-term debt, net-other than bank	1,431,434,000		1,481,004,000
Derivative liabilities	275,000
Estimated fair value | Level 1
Financial assets
Derivative assets	0
Financial liabilities
Derivative liabilities	202,000
Estimated fair value | Level 2
Financial assets
Money market funds	10,000		10,000
Available-for-sale investment and mortgage-related securities	535,264,000		671,358,000
Investment in stock of Federal Home Loan Bank of Seattle	93,413,000		96,022,000
Derivative assets	558,000
Financial liabilities
Deposit liabilities	4,313,560,000		4,235,527,000
Short-term borrowings-other than bank	131,341,000		83,693,000
Other bank borrowings	252,230,000		212,163,000
Long-term debt, net-other than bank	1,431,434,000		1,481,004,000
Derivative liabilities	73,000
Estimated fair value | Level 3
Financial assets
Loans receivable, net	4,149,137,000		3,957,752,000
Estimated fair value | American Savings Bank (ASB)
Financial liabilities
Loan commitments and unused lines and letters of credit	600,000		1,200,000
Servicing rights on loans	$ 16,600,000		$ 11,900,000

[1] Derivatives are carried at fair value with changes in value reflected in the balance sheet in other assets or other liabilities and included in mortgage banking income.