Earnings per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income attributable to Bryn Mawr Bank Corporation	$ 16,682	$ 10,739	$ 46,656	$ 29,216
Denominator for basic earnings per share – weighted average shares outstanding	20,270,706	17,023,046	20,237,757	16,987,499
Effect of dilutive common shares	167,670	230,936	206,318	254,728
Denominator for diluted earnings per share – adjusted weighted average shares outstanding	20,438,376	17,253,982	20,444,075	17,242,227
Basic earnings per share (in dollars per share)	$ 0.82	$ 0.63	$ 2.31	$ 1.72
Diluted earnings per share (in dollars per share)	$ 0.82	$ 0.62	$ 2.28	$ 1.69
Antidilutive shares excluded from computation of average dilutive earnings per share	22,232	21,621	48,807	47,268