Parent Corporation Only Financial Statements (Details) - Condensed Statements of Cash Flows - USD ($) $ 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
Cash flows from operating activities:
Net income	$ (2,024)	$ 11,856	$ 10,859	$ 10,391	$ 9,568	$ 10,842	$ 10,521	$ 10,379	$ 31,082	$ 41,311	$ 18,565
Adjustments to reconcile net income to net cash provided by operating activities:
Increase in other assets									(14,815)	1,190	2,200
Increase (decrease) in other liabilities									(2,022)	(1,080)	377
Net cash provided by operating activities									49,712	46,231	25,189
Cash flows from investing activities:
Net cash used in investing activities									(427,669)	(504,747)	(140,004)
Cash flows from financing activities:
Cash dividends on common stock									(9,067)	(8,996)	(6,940)
Cash dividends on preferred stock									(22)	(112)	(140)
Redemption of preferred stock									(11,250)
Proceeds from exercise of stock options									767	1,424	878
Net cash provided by financing activities									377,461	532,564	158,970
Decrease in cash and cash equivalents									(496)	74,048	44,155
Cash and cash equivalents at beginning of period									200,895	126,847	82,692
Cash and cash equivalents at end of period	200,399				200,895				200,399	200,895	126,847
Parent Company [Member]
Cash flows from operating activities:
Net income									31,082	41,311	18,565
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed earnings of subsidiary									(21,926)	(32,472)	(9,890)
Increase in other assets									2,023	(820)	(1,979)
Increase (decrease) in other liabilities									544	(1,840)	(1,010)
Net cash provided by operating activities									11,723	6,926	5,909
Cash flows from investing activities:
Capital infusion to subsidiary									(38,439)	(35,000)
Net cash used in investing activities									(38,439)	(35,000)
Cash flows from financing activities:
Proceeds from subordinated debt										50,000
Cash dividends on common stock									(9,067)	(8,996)	(6,940)
Cash dividends on preferred stock									(22)	(112)	(140)
Secondary offering and issuance of common stock									38,439
Redemption of preferred stock									(11,250)
Proceeds from exercise of stock options									767	1,424	878
Net cash provided by financing activities									18,867	42,316	(6,202)
Decrease in cash and cash equivalents									(7,849)	14,583	(11)
Cash and cash equivalents at beginning of period									14,857	274	285
Cash and cash equivalents at end of period	$ 7,008				$ 14,857				$ 7,008	$ 14,857	$ 274