Stock-Based Compensation (Number of Shares to be issued upon Exercise of Outstanding Stock-Based Awards and Remaining Shares Available for Future Issuance under all Equity Compensation Plans) (Parenthetical) (Detail) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2009	Dec. 31, 2007	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Employee Stock Ownership Plan (ESOP) Disclosures
Outstanding options awarded in connection with mergers and acquisitions			25	119	265	546
Weighted-average exercise price of the outstanding options			$ 19.17	$ 14.97	$ 14.25	$ 20.72
Number of shares to be issued based on predefined performance targets			9,731
Additional shares approved by shareholders included under Bancorp's 1993 Stock Purchase Plan	12,000	1,500
Shares Available for Future Issuance			24,607
Performance Share Awards
Employee Stock Ownership Plan (ESOP) Disclosures
Number of shares to be issued based on predefined performance targets			2,000
Series of Individually Immaterial Business Acquisitions
Employee Stock Ownership Plan (ESOP) Disclosures
Outstanding options awarded in connection with mergers and acquisitions			20
Weighted-average exercise price of the outstanding options			$ 14.05
2014 Incentive Compensation Plan
Employee Stock Ownership Plan (ESOP) Disclosures
Stock authorized for issuance					36,000
2014 Incentive Compensation Plan | Shares For Full Value Awards
Employee Stock Ownership Plan (ESOP) Disclosures
Stock authorized for issuance					16,000
Shares Available for Future Issuance					4,000