Business Combinations - Schedules of Assets and Liabilities Assumed (Details) - USD ($) $ in Thousands	May 01, 2018	Dec. 15, 2017	Mar. 31, 2019	Dec. 31, 2018
Liabilities assumed:
Goodwill			$ 184,012	$ 184,012
Domenick
Consideration paid:
Cash paid at closing	$ 750
Contingent payment liability (present value)	706
Value of consideration	1,456
Assets acquired:
Cash and due from banks	370
Premises and equipment	1
Other assets	316
Total assets	1,466
Liabilities assumed:
Accounts payable	657
Other liabilities	30
Total liabilities	687
Net assets acquired	779
Goodwill	677
Domenick | Customer Relationships
Assets acquired:
Intangible assets	$ 779
RBPI
Consideration paid:
Common shares issued (3,101,316)		$ 136,768
Cash in lieu of fractional shares		7
Cash-out of certain options		112
Fair value of warrants assumed		1,853
Value of consideration		$ 138,740
Shares issued (in shares)		3,101,316
Assets acquired:
Cash and due from banks		$ 17,092
Premises and equipment		8,264
Other assets		13,611
Investment securities available for sale		121,587
Loans		566,228
Deferred income taxes		34,823
Bank-owned life insurance		16,550
Total assets		783,391
Liabilities assumed:
Other liabilities		31,381
Deposits		593,172
FHLB and other long-term borrowings		59,568
Short-term borrowings		15,000
Junior subordinated debentures		21,416
Unfavorable lease liability		322
Total liabilities		720,859
Net assets acquired		62,532
Goodwill		76,208
RBPI | Core Deposits
Assets acquired:
Intangible assets		4,670
RBPI | Off-Market Favorable Lease
Assets acquired:
Intangible assets		$ 566