Business Combinations - Additional Information (Details) - USD ($) $ in Thousands						3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 01, 2016	Aug. 01, 2016	Mar. 03, 2015	Feb. 27, 2015	Feb. 26, 2015	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill						$ 28,598	$ 15,968		$ 28,598		$ 15,968
Securities transferred in satisfaction of other borrowings										$ 98,316
Repayment of other borrowings										1,659
Business acquisition, bargain purchase gain								$ 1,708		$ 14,217
Southern Transportation Insurance Agency, Ltd.
Business Acquisition [Line Items]
Cash paid for business acquisition	$ 2,150
Southern Transportation Insurance Agency, Ltd. | Banking
Business Acquisition [Line Items]
Intangible asset	1,580
Goodwill	$ 570
ColoEast Bankshares, Inc.
Business Acquisition [Line Items]
Cash paid for business acquisition		$ 70,000
Intangible asset		7,238
Goodwill		$ 12,059
Business acquisition, percentage of voting interests acquired		100.00%
TARP Preferred stock, redemption date									Aug. 31, 2016
Business acquisition, related costs						$ 1,618			$ 1,618
Total consideration transferred		$ 80,500
ColoEast Bankshares, Inc. | Preferred Stock
Business Acquisition [Line Items]
Preferred stock issued		10,500
ColoEast Bankshares, Inc. | Banking
Business Acquisition [Line Items]
Goodwill		$ 12,059
Doral Money Acquisition
Business Acquisition [Line Items]
Business acquisition, percentage of voting interests acquired				100.00%
CLO management contract acquired - Assets under management				$ 700,000
Total consideration transferred				$ 135,864							135,864
Business acquisition, bargain purchase gain											15,117
Doral Money Acquisition | Measurement Period Adjustments
Business Acquisition [Line Items]
Business acquisition, bargain purchase gain							$ 900	$ 1,708			$ 2,608
Doral Money Acquisition | Secured term loan credit facility
Business Acquisition [Line Items]
Other borrowings payable to third party					$ 99,975
Debt instrument maturity date					Mar. 31, 2015
Repayment of debt instrument			$ 99,975
Securities transferred in satisfaction of other borrowings			98,316
Repayment of other borrowings			$ 1,659
Doral Money Acquisition | Secured term loan credit facility | London Interbank Offered Rate (LIBOR)
Business Acquisition [Line Items]
Debt instrument, marginal interest rate					3.50%
Debt instrument, interest rate description									LIBOR plus 3.5%