Income Taxes (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2016

Dec. 31, 2015

Income Taxes

Schedule of components of provision for income taxes

	Year Ended December 31,
(dollars in thousands)	2015		2014
Current:
Federal	$	120,134	$	116,933
State and local		24,900		21,225
Total current		145,034		138,158
Deferred:
Federal		(10,386)		(8,960)
State and local		(5,201)		(1,626)
Total deferred		(15,587)		(10,586)
Total provision for income taxes	$	129,447	$	127,572

Schedule of components of net deferred income tax assets and liabilities

	December 31,
(dollars in thousands)	2015		2014
Assets:
Deferred compensation expense	$	88,749	$	88,608
Allowance for loan and lease losses and nonperforming assets		53,964		54,677
Investment securities		23,627		15,474
Deferred income and expense		7,725		14,663
State income taxes		9,496		8,688
Total deferred income tax assets	$	183,561	$	182,110
Liabilities:
Leases	$	(45,908)	$	(62,215)
Intangible assets		(2,186)		(2,199)
Other		(9,327)		(7,014)
Total deferred income tax liabilities		(57,421)		(71,428)
Net deferred income tax assets	$	126,140	$	110,682

Schedule of reconciliation of Federal statutory to effective income tax rate

	Year Ended December 31,
	2015				2014
(dollars in thousands)	Amount		Percent		Amount		Percent
Federal statutory income tax expense and rate	$	120,129	35.00	%	$	120,485	35.00	%
State and local taxes, net of federal income tax benefit		12,804	3.73			12,739	3.70
Nontaxable income		(3,570)	(1.04)			(4,972)	(1.44)
Other		84	0.02			(680)	(0.20)
Income tax expense and effective income tax rate	$	129,447	37.71	%	$	127,572	37.06	%

Schedule of reconciliation of unrecognized tax benefits

	Nine Months Ended September 30,
	2016						2015
			Interest						Interest
			and						and
(dollars in thousands)	Tax		Penalties		Total		Tax		Penalties		Total
Balance at January 1,	$	5,903	$	2,935	$	8,838	$	5,748	$	2,972	$	8,720
Additions for current year tax positions		6,268		1,117		7,385		504		—		504
Additions for Reorganization Transactions		115,877		5,459		121,336		—		—		—
Additions for prior years' tax positions:
Accrual of interest and penalties		—		95		95		—		132		132
Other		—		—		—		—		25		25
Reductions for prior years' tax positions:
Expiration of statute of limitations		(530)		(215)		(745)		(467)		(180)		(647)
Other		(12)		(1)		(13)		(31)		—		(31)
Balance at September 30,	$	127,506	$	9,390	$	136,896	$	5,754	$	2,949	$	8,703

	Year Ended December 31,
	2015						2014
					Interest						Interest
					and						and
(dollars in thousands)	Total		Tax		Penalties		Total		Tax		Penalties
Balance at beginning of year	$	8,720	$	5,748	$	2,972	$	8,477	$	5,433	$	3,044
Additions for current year tax positions		680		680		—		589		589		—
Additions for prior years’ tax positions:
Accrual of interest and penalties		178		—		178		542		—		542
Other		122		97		25		342		346		(4)
Reductions for prior years’ tax positions:
Expiration of statute of limitations		(862)		(622)		(240)		(1,230)		(620)		(610)
Balance at end of year	$	8,838	$	5,903	$	2,935	$	8,720	$	5,748	$	2,972