Goodwill And Other Intangible Assets (Narrative) (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Oct. 09, 2015
Goodwill impairment		$ 0	$ 0	$ 0
Goodwill		$ 13,545,000	13,467,000	1,942,034,000	$ 12,300,000
Weighted average amortization period for Core Deposit Intangibles		10 years
Impairment on Core Deposit Premiums		$ 0	0	0
Servicing Asset at Amortized Cost		3,500,000
Fair value of loan servicing rights		4,200,000	3,700,000
Mortgage Servicing Rights (MSR) Impairment (Recovery)	$ 600,000		100,000
Oklahoma Banking [Member]
Goodwill		12,525,000		805,704,000	$ 12,300,000
Texas Banking [Member]
Goodwill		1,020,000		458,489,000
Core Deposits [Member]
Amortization		600,000	300,000	400,000
Servicing Contracts [Member]
Amortization		$ 700,000	$ 600,000	$ 400,000