ORRSTOWN FINANCIAL SERVICES, INC. (PARENT COMPANY ONLY) CONDENSED FINANCIAL INFORMATION - Condensed Statements of Cash Flows (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ 32,881	$ 26,463	$ 16,924
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Deferred income taxes	942	(1,973)	1,776
Share-based compensation	1,949	2,092	1,586
Net change in other assets	(2,046)	6,660	2,053
Net cash provided by operating activities	40,811	30,171	9,090
Cash flows from investing activities:
Net cash (used in) provided by investing activities	(2,013)	(292,565)	18,463
Cash flows from financing activities:
Dividends paid	(8,280)	(7,610)	(6,150)
Payments to repurchase common stock	(1,869)	(1,170)	0
Net cash provided by (used in) financing activities	44,654	331,689	(60,405)
Net increase (decrease) in cash and cash equivalents	83,452	69,295	(32,852)
Cash and cash equivalents at beginning of year	125,258	55,963	88,815
Cash and cash equivalents at end of year	208,710	125,258	55,963
Orrstown Financial Services, Inc.
Cash flows from operating activities:
Net income	32,881	26,463	16,924
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Amortization	59	56	47
Deferred income taxes	(4)	(39)	16
Equity in undistributed income of subsidiaries	(20,109)	(16,350)	(19,379)
Share-based compensation	433	463	236
Net change in other liabilities	(40)	(141)	(423)
Net change in other assets	375	(221)	311
Net cash provided by operating activities	13,595	10,231	(2,268)
Cash flows from investing activities:
Capital contributed to subsidiaries	0	0	(100)
Net cash paid for acquisitions	0	(85)	(8,142)
Net cash (used in) provided by investing activities	0	(85)	(8,242)
Cash flows from financing activities:
Dividends paid	(8,280)	(7,610)	(6,150)
Proceeds from issuance of common stock	1,516	1,628	1,463
Payments to repurchase common stock	(2,383)	(1,887)	(1,772)
Other, net	136	116	(59)
Net cash provided by (used in) financing activities	(9,011)	(7,753)	(6,518)
Net increase (decrease) in cash and cash equivalents	4,584	2,393	(17,028)
Cash and cash equivalents at beginning of year	13,961	11,568	28,596
Cash and cash equivalents at end of year	$ 18,545	$ 13,961	$ 11,568