Parent Company - Only Financial Statements - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities:
Net income attributable to Bryn Mawr Bank Corporation	$ 17,136	$ 16,682	$ 14,688	$ 15,286	$ (6,200)	$ 10,739	$ 9,433	$ 9,044	$ 63,792	$ 23,016	$ 36,036
Adjustments to reconcile net income to net cash provided by operating activities:
Net amortization of investment premiums and discounts									3,044	2,990	3,200
Stock-based compensation									2,750	2,068	1,713
Other, net									532	(788)	79
Investing activities:
Acquisitions, net of cash acquired									(380)	12,301	0
Net cash used in investing activities									(220,218)	(186,984)	(497,438)
Financing activities:
Dividends paid									(19,289)	(14,799)	(13,961)
Net proceeds from issuance of subordinated notes									0	68,829	0
Net purchase of treasury stock through publicly announced plans									(5,936)	0	(7,971)
Cash payments to taxing authorities on employees' behalf from shares withheld from stock-based compensation									(1,639)	(1,140)	(745)
Proceeds from exercise of stock options									1,464	1,498	2,181
Repurchase of warrants from U.S. Treasury									(1,755)	0	0
Net cash provided by financing activities									129,415	163,311	350,908
Change in cash and cash equivalents									(11,568)	9,259	(92,302)
Cash and cash equivalents at beginning of period				60,024				50,765	60,024	50,765	143,067
Cash and cash equivalents at end of period	48,456				60,024				48,456	60,024	50,765
Parent Company
Operating activities:
Net income attributable to Bryn Mawr Bank Corporation									63,792	23,016	36,036
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed income of subsidiaries									(32,779)	(21,053)	(17,600)
Net amortization of investment premiums and discounts									98	154	151
Stock-based compensation									2,750	2,068	1,713
Other, net									2,860	1,241	1,000
Net cash provided by operating activities									36,721	5,426	21,300
Investing activities:
Investment in subsidiaries									0	(15,300)	(15,000)
Net change in trading securities									40	(58)	0
Acquisitions, net of cash acquired									0	531	0
Net cash used in investing activities									40	(14,827)	(15,000)
Financing activities:
Dividends paid									(19,289)	(14,799)	(13,961)
Net proceeds from issuance of subordinated notes									0	68,829	0
Net proceeds from sale of (purchase of) treasury stock for deferred compensation plans									2	(115)	(133)
Net purchase of treasury stock through publicly announced plans									(5,936)	0	(7,971)
Cash payments to taxing authorities on employees' behalf from shares withheld from stock-based compensation									(1,639)	(1,140)	(745)
Proceeds from exercise of stock options									1,464	1,498	2,181
Repurchase of warrants from U.S. Treasury									(1,755)	0	0
Net cash provided by financing activities									(27,153)	54,273	(20,629)
Change in cash and cash equivalents									9,608	44,872	(14,329)
Cash and cash equivalents at beginning of period				$ 68,535				$ 23,663	68,535	23,663	37,992
Cash and cash equivalents at end of period	$ 78,143				$ 68,535				$ 78,143	$ 68,535	$ 23,663