Subsequent Events - Additional Information (Detail) $ / shares in Units, $ in Thousands	Jul. 23, 2019 USD ($) Branch $ / shares shares	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Subsequent Event [Line Items]
Total Assets		$ 12,494,653		$ 12,458,632
Portfolio loans, net of unearned income		7,737,854		7,656,281
Deposits		8,694,928		8,831,633
Total shareholders' equity		$ 2,074,116	$ 2,023,139	$ 1,978,827	$ 1,524,106	$ 1,403,026	$ 1,395,321
Subsequent Event [Member] | Old Line [Member] | Definitive Agreement and Plan of Merger [Member]
Subsequent Event [Line Items]
Total Assets	$ 3,100,000
Portfolio loans, net of unearned income	2,400,000
Deposits	2,400,000
Total shareholders' equity	$ 400,000
Number of branches acquired | Branch	37
Value of acquisition	$ 500,100
Number of shares issued for acquisition | shares	0.7844
Business acquisition, price per share | $ / shares	$ 29.22