Mergers and Acquisitions - Additional Information (Detail) $ in Thousands					3 Months Ended		6 Months Ended
	Jul. 20, 2016 USD ($) shares	Apr. 22, 2016 USD ($) Branch	Feb. 13, 2016 USD ($) shares	Sep. 18, 2015 USD ($) Branch	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Goodwill recorded as a result of merger					$ 1,021,247		$ 1,021,247		$ 833,086
Merger-related expenses					10,551	$ 371	35,491	$ 371
Fifth Third Bank Branches [Member]
Business Acquisition [Line Items]
Number of branch-banking locations acquired | Branch		17
Deposits acquired as a result of merger		$ 302,529
Goodwill recorded as a result of merger		11,400
Core deposit intangibles recorded as result of the acquisition		5,952
Assets acquired as a result of merger		317,596
Cash acquired as a result of merger		198,872
Loans acquired as a result of merger		97,734
Fixed and other assets acquired as a result of merger		$ 15,000
Percentage of premium on acquired loan		1.97%
Metro Bancorp Inc [Member]
Business Acquisition [Line Items]
Deposits acquired as a result of merger			$ 2,328,238
Goodwill recorded as a result of merger			177,000
Core deposit intangibles recorded as result of the acquisition			36,801
Assets acquired as a result of merger			2,798,248
Cash acquired as a result of merger			46,890
Loans acquired as a result of merger			1,868,873
Value of acquisition			$ 404,031
Common shares issued | shares			34,041,181
Common shares acquired | shares			14,345,319
Merger-related expenses							31,400
Issuance costs incurred in connection with acquisition					$ 700		$ 700
Metro Bancorp Inc [Member] | Merger - Related Expenses [Member]
Business Acquisition [Line Items]
Severance costs					40.80%		40.80%
Bank of America Branches [Member]
Business Acquisition [Line Items]
Number of branch-banking locations acquired | Branch				5
Deposits acquired as a result of merger				$ 154,619
Goodwill recorded as a result of merger				1,500
Core deposit intangibles recorded as result of the acquisition				3,000
Assets acquired as a result of merger				153,134
Cash acquired as a result of merger				148,159
Loans acquired as a result of merger				842
Fixed and other assets acquired as a result of merger				$ 2,000
Percentage of premium on acquired loan				1.96%
Yadkin Financial Corporation (YDKN) [Member] | Subsequent Event [Member]
Business Acquisition [Line Items]
Assets acquired as a result of merger	$ 7,500,000
Value of acquisition	$ 1,400,000
Common shares issued | shares	111,000,000
Number of shares entitled to receive as per merger agreement, Ratio	2.16
Common shares to be acquired, shares | shares	51,400,000