Borrowings (Additional Information) (Details) - USD ($)		1 Months Ended
	Aug. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	May 31, 2015
Debt Disclosure [Abstract]
FHLB advances		$ 5,140,000,000
Additional borrowing availability through the FHLB		7,000,000
Debt Instrument [Line Items]
Long-term borrowings, Amount		597,847,000	$ 242,391,000
Subordinated debt obligations: floating-rate based on three-month LIBOR plus 3.25 % due in 2032 (5)				$ 18,600,000
Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 145,000,000
Long-term borrowings, Amount	125,000,000	124,625,000	$ 25,000,000
Repayment of debt	25,000,000
Line of Credit | Term Line of Credit [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	125,000,000
Line of Credit | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	20,000,000
Line of Credit Acquired in Merger With Talmer [Member] | Line of Credit
Debt Instrument [Line Items]
Repayment of debt	37,500,000
Talmer
Debt Instrument [Line Items]
Debt assumed in acquisition	$ 687,100,000
Repayment of assumed debt		$ 142,200,000