Loans - Outstanding Principal and Carrying Amount of Acquired Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Outstanding principal balance and the carrying amount of loan acquired [Abstract]
Outstanding principal balance	$ 437,461	$ 63,619
Carrying amount	420,066	58,886
Outstanding principal balance and the carrying amount of loan acquired, impaired [Abstract]
Outstanding principal balance	59,353	24,500
Carrying amount	$ 48,733	$ 20,611