Parent Company - Only Financial Statements - Condensed Statements of Income (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
Condensed Income Statements, Captions [Line Items]
Dividends									$ 6	$ 99	$ 215
Income before equity in undistributed income of subsidiaries									77,957	57,246	54,204
Income before income taxes	$ 18,877	$ 20,747	$ 18,418	$ 19,915	$ 13,724	$ 15,505	$ 14,338	$ 13,679	77,957	57,246	54,204
Income tax expense	1,746	4,066	3,723	4,630	19,924	4,766	4,905	4,635	14,165	34,230	18,168
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
Parent Company
Condensed Income Statements, Captions [Line Items]
Dividends									30,900	950	17,718
Net interest and other income									2,615	2,761	2,714
Total operating income									33,515	3,711	20,432
Expenses									3,527	2,782	2,443
Income before equity in undistributed income of subsidiaries									29,988	929	17,989
Equity in undistributed income of subsidiaries									32,779	21,053	17,600
Income before income taxes									62,767	21,982	35,589
Income tax expense									(1,025)	(1,034)	(447)
Net income attributable to Bryn Mawr Bank Corporation									$ 63,792	$ 23,016	$ 36,036