Acquisition - Summary (Details) - USD ($) $ in Thousands	Dec. 02, 2016	Oct. 01, 2015	Dec. 31, 2016	Dec. 31, 2015
Fair Value of Liabilities Assumed
Goodwill			$ 186,483	$ 164,500
First Community Bank
Consideration Paid
Cash Paid to shareholders		$ 14,750
Total consideration paid		14,750
Fair Value of Assets Acquired
Cash and cash equivalents		11,217
Investment Securities		25,980
FHLB Stock		832
Loans		61,173
Premises and other equipment		1,801
Core deposit intangible		172
Other real estate		816
Other assets		1,115
Total assets acquired		103,106
Fair Value of Liabilities Assumed
Deposits		90,311
Other Liabilities		1,115
Total liabilities assumed		91,426
Total Fair Value of Identifiable Net Assets		11,680
Goodwill		$ 3,070
FirstMerit Bank, NA, Branch Acquisition [Member]
Consideration Paid
Cash Paid to shareholders	$ (476,555)
Total consideration paid	(476,555)
Fair Value of Assets Acquired
Cash and cash equivalents	2,914
Loans	102,097
Premises and other equipment	4,562
Core deposit intangible	11,330
Other assets	294
Total assets acquired	121,197
Fair Value of Liabilities Assumed
Deposits	619,729
Other Liabilities	70
Total liabilities assumed	619,799
Total Fair Value of Identifiable Net Assets	(498,602)
Goodwill	$ 22,047