Acquisitions - Additional Information (Details)		3 Months Ended
	Jan. 04, 2019 USD ($) Branch $ / shares shares	Mar. 31, 2020 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)
Business Acquisition [Line Items]
Merger related expenses		$ 0			$ 2,860,000
Highlands Bancorp, Inc.
Business Acquisition [Line Items]
Number of bank branches operated | Branch	4
Business acquisition, conversion, shares issued (in shares) | shares	1.015
Consideration paid through common stock (in shares) | shares	2,837,524
Stock option payout price per share (in dollars per share) | $ / shares	$ 14.71
Average strike price (in dollars per share) | $ / shares	$ 8.09
Cash paid for redemption of stock options	$ 797,000
Goodwill adjustments			$ 447,000,000	$ 1,700,000
Identifiable intangible assets	$ 3,728,000
Useful life	10 years
Merger related expenses		$ 0			$ 2,900,000