Condensed Consolidated Balance Sheets (Unaudited) - Scenario, Unspecified [Domain] - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Assets
Cash and due from banks	$ 166,933,000	$ 176,830,000
Short-term investments and interest bearing deposits	48,711,000	489,614,000
Securities available-for-sale (amortized cost of $1,547,642 in 2015 and $1,324,408 in 2014)	1,545,699,000	1,318,935,000
Loans held for sale	0	973,000
Loans	9,502,008,000	8,914,080,000
Less: Allowance for loan losses	(153,437,000)	(161,420,000)
Unamortized deferred loan fees, net	(10,207,000)	(12,392,000)
Loans, net	9,338,364,000	8,740,268,000
Federal Home Loan Bank stock	17,250,000	30,785,000
Other real estate owned, net	23,839,000	31,477,000
Affordable housing investments and alternative energy partnerships, net	160,419,000	104,579,000
Premises and equipment, net	97,616,000	99,682,000
Customers’ liability on acceptances	26,378,000	35,656,000
Accrued interest receivable	27,747,000	25,364,000
Goodwill	316,340,000	316,340,000
Other intangible assets, net	2,948,000	3,237,000
Other assets	146,072,000	143,106,000
Total assets	11,918,316,000	11,516,846,000
Deposits
Non-interest-bearing demand deposits	1,671,970,000	1,664,914,000
Interest-bearing deposits:
NOW deposits	871,126,000	778,691,000
Money market deposits	1,682,999,000	1,538,187,000
Savings deposits	562,602,000	533,940,000
Time deposits	4,550,166,000	4,267,728,000
Total deposits	9,338,863,000	8,783,460,000
Securities sold under agreements to repurchase	400,000,000	450,000,000
Advances from the Federal Home Loan Bank	210,000,000	425,000,000
Other borrowings for affordable housing investments	20,261,000	19,934,000
Long-term debt	119,136,000	119,136,000
Acceptances outstanding	26,378,000	35,656,000
Other liabilities	134,613,000	80,772,000
Total liabilities	$ 10,249,251,000	$ 9,913,958,000
Commitments and contingencies
Stockholders’ Equity
Common stock, $0.01 par value, 100,000,000 shares authorized, 84,232,727 issued and 80,025,162 outstanding at June 30, 2015, and 84,022,118 issued and 79,814,553 outstanding at December 31, 2014	$ 842,000	$ 840,000
Additional paid-in-capital	790,897,000	789,519,000
Accumulated other comprehensive loss, net	(2,782,000)	(5,569,000)
Retained earnings	1,005,844,000	943,834,000
Treasury stock, at cost (4,207,565 shares at June 30, 2015, and at December 31, 2014)	(125,736,000)	(125,736,000)
Total equity	1,669,065,000	1,602,888,000
Total liabilities and equity	$ 11,918,316,000	$ 11,516,846,000