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