Borrowings and Subordinated Debentures - Subordinated Debentures (Details)	9 Months Ended
	Sep. 30, 2016 USD ($) trust	Dec. 31, 2015 USD ($)
Borrowings and Subordinated Debentures
Junior subordinated debenture owed to unconsolidated subsidiary trust	$ 25,774,000	$ 25,774,000
Number of Delaware trust affiliates | trust	2
Royal Bancshares Capital Trust I [Member] | Common Stock [Member]
Borrowings and Subordinated Debentures
Aggregate principal amount, common securities	$ 387,000
Royal Bancshares Capital Trust I [Member] | Trust Preferred Securities [Member]
Borrowings and Subordinated Debentures
Aggregate principal amount, capital securities	12,500,000
Trust I [Member]
Borrowings and Subordinated Debentures
Junior subordinated debenture owed to unconsolidated subsidiary trust	$ 12,900,000
Interest rate on notes payable (as a percent)	3.00%
Trust I [Member] | London Interbank Offered Rate (LIBOR) [Member]
Borrowings and Subordinated Debentures
Description of variable rate basis on notes payable	3-month LIBOR
Trust preferred securities basis spread on variable rate (as a percent)	2.15%
Trust II [Member]
Borrowings and Subordinated Debentures
Junior subordinated debenture owed to unconsolidated subsidiary trust	$ 12,900,000
Interest rate on notes payable (as a percent)	3.00%
Trust II [Member] | London Interbank Offered Rate (LIBOR) [Member]
Borrowings and Subordinated Debentures
Description of variable rate basis on notes payable	3-month LIBOR