Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating activities:
Net income	$ 50,244	$ 64,080	$ 53,533
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	10,964	12,986	7,790
Depreciation of premises and equipment	8,557	7,477	6,333
Amortization of fees and discounts, net	19,082	19,626	18,490
Amortization of intangible assets	3,078	2,438	1,847
Increase in accrued interest receivable	(2,378)	(2,009)	(1,334)
(Increase) decrease in other assets	(2,517)	443	(1,643)
Origination of loans held for sale	(354,659)	(366,859)	(573,703)
Proceeds from sales of loans held for sale	369,986	346,895	563,588
Gain on mortgage banking activity, net	(6,293)	(7,434)	(5,896)
Gain on sale of securities, net	(1,984)	(2,369)	(1,478)
Debt extinguishment costs	(695)	0	0
Stock-based compensation expense	3,396	3,046	4,095
(Decrease) increase in accrued interest payable	(114)	350	(203)
Increase in other liabilities	7,353	3,709	6,502
Loss on sale of OREO and valuation adjustments, net	217	313	319
Provision for legal settlement	12,000	0	0
Increase in value of bank-owned life insurance	(1,130)	(2,551)	(776)
Deferred income tax expense	17,899	5,370	2,231
Increase in capitalized interest, net	(4,228)	(5,331)	(5,518)
Net cash provided by operating activities	130,168	80,180	74,177
Investing activities:
Maturities and calls of investment securities	1,230	2,890	5,551
Sales of investment securities available for sale	457,046	201,580	192,933
BOLI - cash return of capital	371	0	0
Purchases of investment securities available for sale	(696,581)	(371,590)	(277,963)
Repayments of investment securities available for sale	197,765	85,200	100,485
Purchases of investment securities held to maturity	0	(3,329)	(48,184)
Net cash for business combinations	0	39,794	40,863
Net increase in loans	(343,858)	(217,572)	(275,162)
Purchases of VISA Class B stock	(10,072)	(387)	(3,589)
Purchases of stock of Federal Home Loan Bank of Pittsburgh	(160,089)	(88,176)	(66,955)
Redemptions of stock of Federal Home Loan Bank of Pittsburgh	167,053	80,447	59,714
Sales of OREO, net	6,077	4,423	4,828
Investment in premises and equipment, net	(7,728)	(9,873)	(8,362)
Net cash used for investing activities	(388,786)	(276,593)	(275,841)
Financing Activities:
Net increase in demand and savings deposits	353,521	272,544	159,587
Decrease in time deposits	35,887	(51,416)	(103,710)
(Decrease) increase in brokered deposits	90,482	(17,928)	(30,228)
(Decrease) increase in loan payable	(338)	(370)	61
Repayment of securities sold under agreement to repurchase	0	0	(25,000)
Receipts from federal funds purchased and securities sold under agreement to repurchase	23,008,000	27,702,620	31,887,100
Repayments of federal funds purchased and securities sold under agreement to repurchase	(23,110,000)	(27,700,820)	(31,862,125)
Receipts from FHLB advances	143,852,751	121,977,563	63,310,841
Repayments of FHLB advances	(143,996,986)	(121,792,841)	(63,047,221)
Repayment of long-term debt	0	(10,000)	0
Dividends paid	(9,425)	(7,632)	(6,002)
Issuance of common stock and exercise of common stock options	3,421	1,900	3,160
Repayment of senior debt	(55,000)	0	0
Issuance of senior debt	0	97,849	0
Buy back of common stock	(11,752)	(14,312)	(31,659)
Net cash provided by (used for) financing activities	160,561	457,157	254,804
Increase in cash and cash equivalents	(98,057)	260,744	53,140
Cash and cash equivalents at beginning of year	821,923	561,179	508,039
Cash and cash equivalents at end of year	723,866	821,923	561,179
Supplemental Disclosure of Cash Flow Information:
Cash paid in interest during the year	33,569	22,483	15,978
Cash paid for income taxes, net	31,441	24,825	23,404
Loans transferred to OREO	5,206	2,251	3,725
Loans transferred to portfolio from held-for-sale at fair value	13,142	12,919	(1,499)
Fair value of assets acquired, net of cash received	0	534,375	340,238
Fair value of liabilities assumed	0	589,632	346,181
Reissuance of treasury stock for acquisitions, net	0	0	71,345
Non-cash goodwill adjustments, net	$ (1,532)	$ 2,112	$ 136