Basis of Presentation - Additional Information (Detail)		9 Months Ended	11 Months Ended
	Sep. 30, 2015 Location Office shares	Sep. 30, 2015 shares	Sep. 30, 2015 shares	Apr. 28, 2015 shares	Dec. 31, 2014 shares	Oct. 28, 2014 shares	Sep. 30, 2014 shares
Basis Of Presentation [Line Items]
Number of locations	70
Number of mortgage origination offices | Office	3
Common stock, shares authorized | shares	120,000,000	120,000,000	120,000,000	120,000,000	120,000,000		120,000,000
Stock repurchase program expiration date		Sep. 30, 2017
Minimum number of shares that company is required to repurchase | shares		0
Stock repurchased under authorization | shares			0
Subsidiary of Common Parent [Member]
Basis Of Presentation [Line Items]
Number of locations	9
Maximum [Member]
Basis Of Presentation [Line Items]
Stock repurchase program, number of shares authorized to be repurchased | shares						1,500,000
Abilene [Member]
Basis Of Presentation [Line Items]
Number of locations	11
Abilene [Member] | Subsidiary of Common Parent [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Cleburne [Member]
Basis Of Presentation [Line Items]
Number of locations	2
Conroe [Member]
Basis Of Presentation [Line Items]
Number of locations	2
Huntsville [Member]
Basis Of Presentation [Line Items]
Number of locations	2
Stephenville [Member]
Basis Of Presentation [Line Items]
Number of locations	2
Stephenville [Member] | Subsidiary of Common Parent [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Granbury [Member]
Basis Of Presentation [Line Items]
Number of locations	2
San Angelo [Member]
Basis Of Presentation [Line Items]
Number of locations	3
San Angelo [Member] | Subsidiary of Common Parent [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Weatherford [Member]
Basis Of Presentation [Line Items]
Number of locations	3
Mineral Wells [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Montgomery [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Hereford [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Hereford [Member] | Subsidiary of Common Parent [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Sweetwater [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Sweetwater [Member] | Subsidiary of Common Parent [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Tomball [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Eastland [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Ranger [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Rising Star [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Cisco [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Southlake [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Number of mortgage origination offices | Office	1
Grapevine [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Aledo [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Willow Park [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Brock [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Alvarado [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Beaumont [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Beaumont [Member] | Subsidiary of Common Parent [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Burleson [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Cut and Shoot [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Keller [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Magnolia [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Trophy Club [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Boyd [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Bridgeport [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Decatur [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Roby [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Trent [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Merkel [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Clyde [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Moran [Member]
Basis Of Presentation [Line Items]
Number of locations	1
New Waverly [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Albany [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Midlothian [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Glen Rose [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Odessa [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Odessa [Member] | Subsidiary of Common Parent [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Waxahachie [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Willis [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Acton [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Fort Worth [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Fort Worth [Member] | Subsidiary of Common Parent [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Orange [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Newton [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Port Arthur [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Vidor [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Mauriceville [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Lubbock [Member] | Subsidiary of Common Parent [Member]
Basis Of Presentation [Line Items]
Number of locations	1
Dallas [Member]
Basis Of Presentation [Line Items]
Number of mortgage origination offices | Office	1
Ft. Worth [Member]
Basis Of Presentation [Line Items]
Number of mortgage origination offices | Office	1