Loans - Acquired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Oct. 17, 2014
Credit impaired acquired loans:
Outstanding principal balance	$ 60,554	$ 16,224
Recorded investment	46,174	14,154
Discount, net	14,380	2,070
Other acquired loans:
Outstanding principal balance	1,162,068	226,284
Deferred fees, net	(162)	(3)
Recorded investment	1,150,938	224,270
Discount, net	10,968	2,011
Total acquired loans:
Outstanding principal balance	1,222,622	242,508
Deferred fees, net	(162)	(3)
Recorded investment	1,197,112	238,424
Discount, net	25,348	4,081
Changes in the accretable yield for credit impaired acquired loans
Beginning balance	685	603
Additions	(71)	62
Reclassifications from nonaccretable yield	563	161
Accretion	(211)	(141)
Balance at period end	966	$ 685
SP Bancorp Inc And Its Wholly Owned Subsidiary Share Plus Bank [Member]
Credit impaired acquired loans:
Outstanding principal balance	50,325		$ 52,053
Recorded investment	37,538		38,581
Discount, net	12,787		13,472
Other acquired loans:
Outstanding principal balance	1,019,212		1,055,998
Deferred fees, net	(144)
Recorded investment	1,008,960		1,042,414
Discount, net	10,108		13,584
Total acquired loans:
Outstanding principal balance	1,069,537		1,108,051
Deferred fees, net	(144)
Recorded investment	1,046,498		1,080,995
Discount, net	$ 22,895		$ 27,056