Acquisitions (Schedule of Fair Value of Net Assets Acquired Acquired and Liabilities Assumed) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Apr. 28, 2017	Mar. 10, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill	$ 745,523			$ 621,193
FNBC Transaction [Member]
Business Acquisition [Line Items]
Cash and due from banks	160,788
Interest-bearing time deposits with other banks	382,622
Fed funds sold and other short-term investments	148
Securities	213,877
Total Loans	1,368,669
Property and equipment	20,934
Accrued interest receivable	4,028
Identifiable intangible assets	25,300
Deferred tax asset	2,220
Other assets	4,213
Total identifiable assets	2,182,799
Deposits	1,928,509
Short-term borrowings	596,635
Long-term debt	93,120
Other liabilities	4,686
Total liabilities	2,622,950
Net identifiable assets acquired (liabilities assumed)	(440,151)
Consideration (Paid) Received	315,821
Goodwill	$ 124,330
FNBC I [Member]
Business Acquisition [Line Items]
Cash and due from banks			$ 2,856
Total Loans			1,203,092
Property and equipment			11,946
Accrued interest receivable			3,143
Identifiable intangible assets			3,900
Deferred tax asset			856
Other assets			63
Total identifiable assets			1,225,856
Deposits			398,171
Short-term borrowings			510,749
Long-term debt			93,120
Other liabilities			1,607
Total liabilities			1,003,647
Net identifiable assets acquired (liabilities assumed)			222,209
Consideration (Paid) Received			(325,756)
Goodwill			$ 103,547
FNBC II [Member]
Business Acquisition [Line Items]
Cash and due from banks		$ 157,932
Interest-bearing time deposits with other banks		382,622
Fed funds sold and other short-term investments		148
Securities		213,877
Total Loans		165,577
Property and equipment		8,988
Accrued interest receivable		885
Identifiable intangible assets		21,400
Deferred tax asset		1,364
Other assets		4,150
Total identifiable assets		956,943
Deposits		1,530,338
Short-term borrowings		85,886
Other liabilities		3,079
Total liabilities		1,619,303
Net identifiable assets acquired (liabilities assumed)		(662,360)
Consideration (Paid) Received		641,577
Goodwill		$ 20,783