Segment Reporting - Schedule of Segment Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Net interest income	$ 27,617	$ 24,135	$ 81,918	$ 68,576
Provision for loan losses	71	(1,159)	(727)	(937)
Mortgage banking income	36,938	19,794	91,574	51,081
Other noninterest income	7,024	7,254	21,779	17,190
Depreciation and amortization	972	821	2,994	2,383
Amortization of core deposit intangibles	526	415	1,605	1,221
Amortization and impairment of mortgage servicing rights	5,198	764	14,310	1,543
Other noninterest expense	48,833	33,579	128,562	91,465
Income before income taxes	15,979	16,763	48,527	41,172
Income tax expense	14,772	858	16,946	2,507
Net income	1,207	15,905	31,581	38,665
Total assets	3,187,180	2,876,340	3,187,180	2,876,340	$ 2,899,420
Goodwill	46,867	46,904	46,867	46,904	$ 46,904
Banking Segment
Segment Reporting Information [Line Items]
Net interest income	28,158	23,625	83,389	67,461
Provision for loan losses	71	(1,159)	(727)	(937)
Mortgage banking income	8,878	5,875	22,237	14,227
Other noninterest income	7,024	7,254	21,779	17,190
Depreciation and amortization	927	793	2,729	2,207
Amortization of core deposit intangibles	526	415	1,605	1,221
Other noninterest expense	30,332	21,573	81,202	60,698
Income before income taxes	12,204	15,132	42,596	35,689
Total assets	2,661,116	2,534,915	2,661,116	2,534,915
Goodwill	46,767	46,804	46,767	46,804
Mortgage Segment
Segment Reporting Information [Line Items]
Net interest income	(541)	510	(1,471)	1,115
Mortgage banking income	28,060	13,919	69,337	36,854
Depreciation and amortization	45	28	265	176
Amortization and impairment of mortgage servicing rights	5,198	764	14,310	1,543
Other noninterest expense	18,501	12,006	47,360	30,767
Income before income taxes	3,775	1,631	5,931	5,483
Total assets	526,064	341,425	526,064	341,425
Goodwill	$ 100	$ 100	$ 100	$ 100