Selected Financial Data - Summary of Selected Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Interest income	$ 59,096	$ 57,808	$ 55,850	$ 55,019	$ 53,353	$ 53,669	$ 52,611	$ 43,916	$ 227,774	$ 203,548	$ 160,523
Interest expense	6,638	6,353	6,142	5,382	4,468	4,073	3,800	3,657	24,515	15,997	12,481
Provision for loan losses	5,586	2,516	4,848	5,014	3,915	3,206	2,059	1,207	17,965	10,388	1,715
Net Interest Income After Provision for Loan Losses	46,872	48,939	44,860	44,623	44,970	46,390	46,752	39,052	185,294	177,163	146,327
Security gains, net	0	0	0	0	0	0	(34)	0
Noninterest income	12,922	13,448	12,448	15,817	13,084	12,481	13,417	12,084	54,635	51,033	46,338
Noninterest expense	35,625	34,439	34,753	38,416	33,817	33,829	35,449	33,621	143,232	136,717	117,240
Income before taxes	24,169	27,948	22,555	22,024	24,237	25,042	24,686	17,515
Provision for income taxes	6,510	7,367	5,496	5,931	6,814	6,407	6,498	4,680	25,305	24,398	17,515
Net Income Available to Common Shareholders	$ 17,659	$ 20,581	$ 17,059	$ 16,093	$ 17,423	$ 18,635	$ 18,188	$ 12,835	$ 71,167	$ 66,801	$ 57,745
Common earnings per share-diluted (in USD per share)	$ 0.51	$ 0.59	$ 0.49	$ 0.46	$ 0.50	$ 0.54	$ 0.52	$ 0.41	$ 2.05	$ 1.98	$ 1.95
Dividends declared per common share (in USD per share)	0.20	0.19	0.19	0.19	0.19	0.18	0.18	0.18	$ 0.77	$ 0.73	$ 0.68
Common book value (in USD per share)	$ 24.12	$ 24.02	$ 23.63	$ 23.23	$ 22.76	$ 22.63	$ 22.15	$ 21.91