Operating Expenses (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Expenses [Abstract]
Salaries and wages									$ 104,490	$ 83,229	$ 78,014
Employee benefits									23,430	19,328	18,405
Occupancy									18,213	15,842	13,934
Equipment and software									18,569	14,737	13,734
Outside processing/service fees									15,207	11,586	11,134
FDIC insurance premiums									5,485	4,307	4,362
Professional fees									4,842	3,570	3,771
Postage and express mail									3,313	3,418	3,051
Advertising and marketing									3,288	3,051	2,971
Donations									1,375	1,155	2,829
Training, travel and other employee expenses									3,224	2,480	2,512
Telephone									2,608	1,966	1,940
Intangible asset amortization									4,389	2,029	1,909
Supplies									2,216	1,897	1,670
Credit-related expenses									632	996	707
Business Combination, Acquisition Related Costs									7,804	6,388	0
Other									4,809	3,946	4,005
Total Operating Expenses	$ 57,824	$ 58,265	$ 56,785	$ 51,020	$ 52,616	$ 42,702	$ 42,425	$ 42,182	$ 223,894	$ 179,925	$ 164,948