Mergers and Acquisitions - Amounts Recorded on Consolidated Balance Sheet in Conjunction with Acquisition (Detail) - USD ($) $ in Thousands	Feb. 13, 2016	Sep. 18, 2015
Business Acquisition [Line Items]
Cash and cash equivalents		$ 148,159
Total identifiable assets acquired		154,619
Deposits		154,619
Metro Bancorp Inc [Member]
Business Acquisition [Line Items]
Fair value of consideration paid	$ 404,020
Cash and cash equivalents	46,854
Securities	722,980
Loans	1,869,046
Other intangible assets	36,801
Other assets	121,518
Total identifiable assets acquired	2,797,199
Deposits	2,327,219
Borrowings	227,539
Other liabilities	12,269
Total liabilities assumed	2,567,027
Fair value of net identifiable assets acquired	230,172
Goodwill recognized	$ 173,848
Bank of America [Member]
Business Acquisition [Line Items]
Cash and cash equivalents		148,159
Loans		842
Other intangible assets		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		$ 1,485