CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Operating activities:
Net income	$ 10,647	$ 10,333	$ 21,460	$ 21,558
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization			3,897	3,504
Provision (credit) for loan and lease losses	2,957	1,218	4,193	1,815	$ 5,371
Share based compensation expense			992	941
Deferred income tax expense			60	116
Origination of loans held for sale			(72,226)	(109,045)
Proceeds from sales of loans held for sale			94,282	101,688
Gains on sales of loans held for sale			(1,517)	(1,576)
Loss on sales of other real estate owned			52	0
Investment securities gains	(150)	(19)	(1,919)	(19)
Increase (Decrease) in Operating Capital [Abstract]
Net (increase) decrease in accrued interest receivable			44	(510)
Net (increase) decrease in other assets			(2,526)	(65)
Net increase (decrease) in accrued expenses and other liabilities			(3,880)	(162)
Other - net			650	2,069
Net cash provided by operating activities			43,562	20,314
Investing activities:
Proceeds of other equity securities			6,994	5,838
Purchases of investments held-to-maturity			0	(2,100)
Purchases of investments available-for-sale			(113,273)	0
Proceeds from sales of investment available-for-sale			40,863	0
Proceeds from maturities, calls and principal payments of investments held-to-maturity			5,004	4,786
Proceeds from maturities, calls and principal payments of investments available-for-sale			179,038	45,249
Net increase in loans and leases			(195,826)	(163,717)
Proceeds from the sales of other real estate owned			1,352	0
Expenditures for premises and equipment			(2,594)	(4,559)
Net cash used in investing activities			(78,442)	(114,503)
Financing activities:
Net increase (decrease) in deposits			246,411	180,837
Net increase (decrease) in retail repurchase agreements and federal funds purchased			8,742	37,385
Proceeds from advances from FHLB			1,290,000	1,174,000
Repayment of advances from FHLB			(1,460,000)	(1,279,000)
Retirement of subordinated debt			(5,000)	0
Proceeds from issuance of common stock			45	13
Tax benefits associated with shared based compensation			267	335
Repurchase of common stock			(13,273)	(14,915)
Dividends paid			(11,622)	(11,041)
Net cash provided by financing activities			55,570	87,614
Net increase (decrease) in cash and cash equivalents			20,690	(6,575)
Cash and cash equivalents at beginning of period			72,882	96,217	96,217
Cash and cash equivalents at end of period	$ 93,572	$ 89,642	93,572	89,642	$ 72,882
Supplemental Disclosures:
Interest payments			11,114	9,619
Income tax payments			12,984	9,876
Transfer of Investments Held-to-maturity to Available For Sale Securities			203,118	0
Transfer from loans to residential mortgage loans held for sale			18,572	0
Transfers from loans to other real estate owned			$ 0	$ 1,340