Operating Segments (Financial Results By Operating Segment) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Financial results by operating segment
Net interest income (loss)	$ 20,163	$ 19,840
Provision for loan losses	1,776	4,375
Noninterest income	4,880	3,415
Noninterest expenses	15,303	15,996
Income before taxes	7,964	2,884
Taxes on income (loss)	2,685	1,015
Net income	5,279	1,869
Externally generated revenue from investing activities	1,300	900
Internally generated loss from fund management	700	800
Total loans at period end	1,936,443	1,781,884
Total assets at period end	2,522,594	2,360,819
Total deposits at period end	1,977,265	1,895,248
Oklahoma Banking [Member]
Financial results by operating segment
Net interest income (loss)	12,794	12,938
Provision for loan losses	1,422	260
Noninterest income	3,260	2,195
Noninterest expenses	9,697	9,960
Income before taxes	4,935	4,913
Taxes on income (loss)	1,663	1,729
Net income	3,272	3,184
Total loans at period end	1,153,417	1,060,483
Total assets at period end	1,189,746	1,105,545
Total deposits at period end	1,358,251	1,359,179
Texas Banking [Member]
Financial results by operating segment
Net interest income (loss)	6,088	5,566
Provision for loan losses	491	1,915
Noninterest income	456	302
Noninterest expenses	3,197	3,731
Income before taxes	2,856	222
Taxes on income (loss)	963	78
Net income	1,893	144
Total loans at period end	639,945	560,421
Total assets at period end	636,350	556,405
Total deposits at period end	192,867	195,593
Kansas Banking [Member]
Financial results by operating segment
Net interest income (loss)	1,558	1,828
Provision for loan losses	(134)	2,199
Noninterest income	302	318
Noninterest expenses	1,407	1,417
Income before taxes	587	(1,470)
Taxes on income (loss)	198	(517)
Net income	389	(953)
Total loans at period end	143,081	160,980
Total assets at period end	141,939	160,031
Total deposits at period end	159,828	130,283
Other Operations [Member]
Financial results by operating segment
Net interest income (loss)	(277)	(492)
Provision for loan losses	(3)	1
Noninterest income	862	600
Noninterest expenses	1,002	888
Income before taxes	(414)	(781)
Taxes on income (loss)	(139)	(275)
Net income	(275)	(506)
Total assets at period end	554,559	538,838
Total deposits at period end	$ 266,319	$ 210,193