Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Taxes [Abstract]

Income Tax Expense

	Years Ended December 31,
(in thousands)	2017		2016		2015
Included in net income
Current federal	$	38,859	$	43,777	$	17,378
Current state		4,112		1,689		4,241
Total current provision		42,971		45,466		21,619
Deferred federal		48,653		(6,127)		15,457
Deferred state		1,178		(1,712)		1,228
Total deferred provision		49,831		(7,839)		16,685
Total included in net income	$	92,802	$	37,627	$	38,304

Deferred Tax Assets and Liabilities

	December 31,
(in thousands)	2017		2016
Deferred tax assets:
Allowance for loan losses	$	51,517	$	89,120
Employee compensation and benefits		9,783		28,401
Loan purchase accounting adjustments		6,441		12,047
Tax credit carryforward		21,274		29,085
Securities		12,250		23,169
State net operating loss		1,979		1,690
Other		15,407		14,583
Gross deferred tax assets		118,651		198,095
State valuation allowance		(1,979)		(1,690)
Subtotal valuation allowance		(1,979)		(1,690)
Net deferred tax assets		116,672		196,405
Deferred tax liabilities:
Fixed assets & intangibles		(56,526)		(74,518)
FDIC indemnification asset		—		(6,293)
Other		(6,167)		(11,159)
Gross deferred tax liabilities		(62,693)		(91,970)
Net deferred tax asset	$	53,979	$	104,435

Effective Income Tax Rate Reconciliation

	Years Ended December 31,
	2017				2016				2015
($ in thousands)	Amount		%		Amount		%		Amount		%
Taxes computed at statutory rate	$	107,952	35.0	%	$	65,423	35.0	%	$	59,418	35.0	%
Increases (decreases) in taxes resulting from:
State income taxes, net of federal income
tax benefit		4,737	1.5			1,917	1.0			2,595	1.5
Tax-exempt interest		(18,870)	(6.1)			(14,497)	(7.8)			(7,849)	(4.6)
Life insurance contracts		(5,360)	(1.7)			(4,833)	(2.6)			(3,798)	(2.2)
Tax credits		(9,374)	(3.0)			(10,518)	(5.6)			(12,495)	(7.4)
Employee share-based compensation		(5,824)	(1.9)			—	—			—	—
Impact of deferred tax asset re-measurement		19,520	6.3			—	—			—	—
Other, net		21	—			135	0.1			433	0.3
Income tax expense	$	92,802	30.1	%	$	37,627	20.1	%	$	38,304	22.6	%