Bank segment - Balance sheet data (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Assets
Available-for-sale investment securities, at fair value	$ 590,648,000us-gaap_AvailableForSaleSecurities	$ 550,394,000us-gaap_AvailableForSaleSecurities
Stock in Federal Home Loan Bank of Seattle, at cost	63,711,000us-gaap_FederalHomeLoanBankStock	69,302,000us-gaap_FederalHomeLoanBankStock
Loans receivable held for investment, net	4,401,504,000	4,389,033,000
Loans held for sale, at lower of cost or fair value	9,906,000us-gaap_LoansReceivableHeldForSaleNet	8,424,000us-gaap_LoansReceivableHeldForSaleNet
Other	481,531,000us-gaap_OtherAssets	542,523,000us-gaap_OtherAssets
Goodwill	82,190,000us-gaap_Goodwill	82,190,000us-gaap_Goodwill
Total assets	11,273,447,000us-gaap_Assets	11,185,142,000us-gaap_Assets
Liabilities
Other	456,338,000us-gaap_OtherLiabilities	531,230,000us-gaap_OtherLiabilities
Total liabilities	9,341,245,000us-gaap_Liabilities	9,360,276,000us-gaap_Liabilities
Commitments and contingencies
Equity [Abstract]
Retained earnings	296,680,000	296,654,000		255,030,000
Accumulated other comprehensive income (loss), net of taxes:
Accumulated other comprehensive loss, net of tax benefits	(23,320,000)	(27,378,000)	(15,583,000)	(16,750,000)
Total shareholders’ equity	1,897,909,000us-gaap_StockholdersEquity	1,790,573,000us-gaap_StockholdersEquity	1,745,124,000us-gaap_StockholdersEquity	1,726,406,000us-gaap_StockholdersEquity
Total liabilities and shareholders’ equity	11,273,447,000	11,185,142,000
Other assets
Property, plant and equipment, net of accumulated depreciation	4,190,835,000us-gaap_PropertyPlantAndEquipmentNet	4,148,774,000us-gaap_PropertyPlantAndEquipmentNet
Total Other Assets	481,531,000us-gaap_OtherAssets	542,523,000us-gaap_OtherAssets
Other liabilities
Total other liabilities	456,338,000us-gaap_OtherLiabilities	531,230,000us-gaap_OtherLiabilities
Balance Sheet related disclosures
Securities sold under agreements to repurchase	212,000,000	191,000,000
American Savings Bank (ASB)
Assets
Cash and due from banks	98,484,000	107,233,000
Interest-bearing deposits	172,517,000	54,230,000
Available-for-sale investment securities, at fair value	590,648,000	550,394,000
Stock in Federal Home Loan Bank of Seattle, at cost	63,711,000	69,302,000
Loans receivable held for investment	4,447,299,000	4,434,651,000
Allowance for loan losses	(45,795,000)	(45,618,000)
Loans receivable held for investment, net	4,401,504,000	4,389,033,000
Loans held for sale, at lower of cost or fair value	9,906,000	8,424,000
Other	305,917,000	305,416,000
Goodwill	82,190,000	82,190,000
Total assets	5,724,877,000	5,566,222,000
Liabilities
Deposit liabilities-noninterest-bearing	1,420,085,000	1,342,794,000
Deposit liabilities-interest-bearing	3,331,243,000	3,280,621,000
Other borrowings	312,094,000	290,656,000
Other	117,849,000	118,363,000
Total liabilities	5,181,271,000	5,032,434,000
Commitments and contingencies
Equity [Abstract]
Common stock	1,000	1,000
Additional paid in capital	338,411,000	338,411,000
Retained earnings	217,909,000	211,934,000
Accumulated other comprehensive income (loss), net of taxes:
Net unrealized losses on securities	3,913,000	462,000
Accumulated other comprehensive loss, net of tax benefits	(16,628,000)	(17,020,000)
Accumulated other comprehensive loss, net of tax benefits	(12,715,000)	(16,558,000)
Total shareholders’ equity	543,606,000	533,788,000
Total liabilities and shareholders’ equity		5,566,222,000
Other assets
Bank-owned life insurance	135,141,000	134,115,000
Property, plant and equipment, net of accumulated depreciation	85,174,000	92,407,000
Prepaid expenses	4,892,000	3,196,000
Accrued interest receivable	13,720,000	13,632,000
Mortgage-servicing rights	11,965,000	11,540,000
Low-income housing equity investments	32,140,000	33,438,000
Real estate acquired in settlement of loans, net	665,000	891,000
Other	22,220,000	16,197,000
Total Other Assets	305,917,000	305,416,000
Other liabilities
Accrued expenses	29,670,000	37,880,000
Federal and state income taxes payable	36,010,000	28,642,000
Cashier's checks	24,686,000	20,509,000
Advance payments by borrowers	5,904,000	9,652,000
Other	21,579,000	21,680,000
Total other liabilities	117,849,000	118,363,000
Balance Sheet related disclosures
Securities sold under agreements to repurchase	212,000,000	191,000,000
Advances from Federal Home Loan Bank	$ 100,000,000	$ 100,000,000

The total of net (gain) loss, prior service cost (credit), and transition assets (obligations), as well as minimum pension liability if still remaining, included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost. This amount is adjusted for regulatory rate making impacts.

No definition available.