Mergers and Acquisitions - Amounts Recorded on Consolidated Balance Sheet in Conjunction with Acquisition (Detail) - USD ($) $ in Thousands		Feb. 13, 2016	Apr. 22, 2016	Sep. 18, 2015
Fifth Third Bank Branches [Member]
Business Acquisition [Line Items]
Cash and cash equivalents			$ 198,872
Loans			97,734
Core deposit intangibles			5,952
Other assets			15,038
Total identifiable assets acquired			317,596
Deposits			302,529
Other liabilities			26,427
Total liabilities assumed			328,956
Fair value of net identifiable assets acquired			(11,360)
Goodwill recognized	[1]		$ 11,360
Metro Bancorp Inc [Member]
Business Acquisition [Line Items]
Fair value of consideration paid		$ 404,031
Cash and cash equivalents		46,890
Securities		722,980
Loans		1,868,873
Core deposit intangibles		36,801
Other assets		122,704
Total identifiable assets acquired		2,798,248
Deposits		2,328,238
Borrowings		227,539
Other liabilities		15,397
Total liabilities assumed		2,571,174
Fair value of net identifiable assets acquired		227,074
Goodwill recognized	[1]	$ 176,957
Bank of America Branches [Member]
Business Acquisition [Line Items]
Cash and cash equivalents				$ 148,159
Loans				842
Core deposit intangibles				3,000
Other assets				1,133
Total identifiable assets acquired				153,134
Deposits				154,619
Total liabilities assumed				154,619
Fair value of net identifiable assets acquired				(1,485)
Goodwill recognized	[1]			$ 1,485

[1] All of the goodwill for these transactions has been recorded by FNBPA.