Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income	$ 120,391	$ 108,680
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan and lease losses	2,600	4,850
Depreciation, amortization, and accretion, net	24,495	15,257
Deferred income taxes	6,662	(10,267)
Other gains, net	(25)	(849)
Originations of loans held for sale		(108,074)
Proceeds from sales of loans held for sale		106,020
Net gains on sales of loans held for sale		(2,107)
Net gains on investment securities	(25,731)	(10,862)
Change in assets and liabilities:
Net decrease (increase) in other assets	14,157	(55,769)
Net decrease in other liabilities	(2,711)	(27,007)
Net cash provided by operating activities	139,838	19,872
Available-for-sale securities:
Proceeds from maturities and principal repayments	551,595	673,725
Proceeds from sales	534,107	1,210,862
Purchases	(1,554,942)	(1,794,137)
Other investments:
Proceeds from sales	11,801	24,310
Purchases	(11,832)	(14,139)
Net increase in loans and leases resulting from originations and principal repayments	(466,843)	(247,206)
Proceeds from bank owned life insurance	1,021
Purchases of premises, equipment, and software	(8,565)	(10,190)
Proceeds from sales of premises and equipment	50	13
Proceeds from sales of other real estate owned	167	5,186
Other	66	70
Net cash used in investing activities	(943,375)	(151,506)
Cash flows from financing activities
Net increase in deposits	60,180	483,697
Net (decrease) increase in short-term borrowings	(181,200)	58,299
Dividends paid	(30,000)
Distributions paid	(363,624)	(74,499)
Net cash (used in) provided by financing activities	(514,644)	467,497
Net (decrease) increase in cash and cash equivalents	(1,318,181)	335,863
Cash and cash equivalents at beginning of period	2,650,195	1,261,453
Cash and cash equivalents at end of period	1,332,014	1,597,316
Supplemental disclosures
Interest paid	12,663	11,089
Income taxes paid, net of income tax refunds	104,792	126,201
Noncash investing and financing activities:
Transfers from loans and leases to other real estate owned	202	1,927
Transfers from loans held for sale to loans and leases		$ 2,158
Derivative liability entered into in connection with sale of investment securities	$ 8,828