Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Other Intangible Assets [Abstract]

Carrying Value of Intangible Assets Subject to Amortization

	December 31, 2017
	Purchase		Accumulated		Carrying
(in thousands)	Value		Amortization		Value
Core deposit intangibles	$	215,955	$	132,878	$	83,077
Credit card and trust relationships		22,400		16,882		5,518
Merchant processing relationships		10,000		7,955		2,045
	$	248,355	$	157,715	$	90,640

	December 31, 2016
	Purchase		Accumulated		Carrying
(in thousands)	Value		Amortization		Value
Core deposit intangibles	$	190,655	$	113,436	$	77,219
Credit card and trust relationships		22,400		14,907		7,493
Merchant processing relationships		10,000		6,955		3,045
	$	223,055	$	135,298	$	87,757

Aggregate Amortization Expense

	Years Ended December 31,
(in thousands)	2017		2016		2015
Aggregate amortization expense for:
Core deposit intangibles	$	19,442	$	16,411	$	18,031
Credit card and trust relationships		1,975		2,172		2,369
Trade name		—		—		2,388
Merchant processing relationships		1,000		1,198		1,396
	$	22,417	$	19,781	$	24,184

Estimated Amortization Expense of Other Intangible Assets

(in thousands)
2018	$	21,368
2019		18,194
2020		13,766
2021		11,288
2022		8,975
Thereafter		17,049
	$	90,640