Business Combinations - fair value of the assets purchased, including goodwill, and liabilities (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jul. 17, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets:
Cash		$ 516,300
Goodwill		25,211	$ 25,309
Liabilities:
Bargain purchase gain		$ 416	$ 0	$ 0
The Bank shares Inc [Member] | Measurement Period Adjustments [Member]
Assets:
Cash	$ 0
Investment securities	0
Loans, net	1,304
Fixed assets	0
OREO	437
Core deposit intangibles	0
Goodwill	(555)
Other assets	(770)
Total assets acquired	416
Liabilities:
Deposits	0
Borrowings	0
Subordinated debt	0
Other liabilities	0
Total liabilities assumed	0
Bargain purchase gain	(416)
The Bank shares Inc [Member] | Scenario, Previously Reported [Member]
Assets:
Cash	34,408
Investment securities	46,366
Loans, net	109,988
Fixed assets	4,191
OREO	2,424
Core deposit intangibles	2,564
Goodwill	555
Other assets	14,163
Total assets acquired	214,659
Liabilities:
Deposits	188,469
Borrowings	1,658
Subordinated debt	5,151
Other liabilities	728
Total liabilities assumed	196,006
The Bank shares Inc [Member] | Restatement Adjustment [Member]
Assets:
Cash	34,408
Investment securities	46,366
Loans, net	111,292
Fixed assets	4,191
OREO	2,861
Core deposit intangibles	2,564
Goodwill	0
Other assets	13,393
Total assets acquired	215,075
Liabilities:
Deposits	188,469
Borrowings	1,658
Subordinated debt	5,151
Other liabilities	728
Total liabilities assumed	$ 196,006