Parent Company Only Financial Information (Statement of Cash Flow) (Details) - 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	Dec. 31, 2013
Operating activities:
Net income	$ 7,408	$ 7,792	$ 7,962	$ 7,995	$ 2,583	$ 4,134	$ 4,913	$ (689)	$ 31,157	$ 10,941	$ 16,684
Depreciation, amortization and accretion, net									19,169	18,503	13,174
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on investment securities	(68)	$ 1	$ (767)	(96)	(56)	$ (62)	$ (11)	(600)	(930)	(729)	(398)
Loss (gain) on debt extinguishment									707	520	(67)
Net cash provided by operating activities									60,311	47,882	31,495
Investing activities:
Business combinations, net of cash received									(244)	97,277	17,081
Net cash used in investing activities									(198,358)	(1,110)	(14,163)
Financing activities:
Proceeds from long-term borrowings									55,000	0	5,269
Payments on long-term borrowings									(24,361)	(72,446)	(10,288)
Purchase of treasury stock									4,965	741	520
Proceeds from issuance of common shares									18	0	40,242
Cash dividends paid									(11,173)	(10,065)	(6,767)
Excess tax benefit from share-based payments									26	51	85
Net cash provided by (used in) financing activities									133,078	(37,111)	(9,698)
Net (decrease) increase in cash and cash equivalents									(4,969)	9,661	7,634
Cash and cash equivalents at beginning of period				71,115				61,454	71,115	61,454	53,820
Cash and cash equivalents at end of period	66,146				71,115				66,146	71,115	61,454
Supplemental cash flow information:
Interest paid									11,773	11,541	10,766
Holding Company
Operating activities:
Net income									31,157	10,941	16,684
Depreciation, amortization and accretion, net									190	165	0
Adjustments to reconcile net income to net cash provided by operating activities:
(Equity in) excess dividends from undistributed earnings of subsidiaries									(12,162)	2,776	999
Other, net									355	(1,903)	1,825
Net cash provided by operating activities									19,540	11,979	19,508
Investing activities:
Investment in subsidiaries									(22,769)	(104,584)	(65,822)
Decrease (increase) in receivable from subsidiary									23,389	(2,860)	(187)
Business combinations, net of cash received									0	83,391	54,386
Net cash used in investing activities									620	(24,053)	(11,623)
Financing activities:
Payments on long-term borrowings									0	(14,400)	(4,800)
Purchase of treasury stock									(5,480)	(741)	(520)
Proceeds from issuance of common shares									18	0	40,242
Cash dividends paid									(11,173)	(10,065)	(6,767)
Excess tax benefit from share-based payments									26	51	85
Net cash provided by (used in) financing activities									(16,609)	(25,155)	28,240
Net (decrease) increase in cash and cash equivalents									3,551	(37,229)	36,125
Cash and cash equivalents at the beginning of year					4,487					4,487	41,716	$ 5,591
Cash and cash equivalents at beginning of period				$ 4,487				$ 41,716	4,487	41,716
Cash and cash equivalents at end of period	$ 8,038				$ 4,487				8,038	4,487	41,716
Supplemental cash flow information:
Interest paid									$ 433	$ 594	$ 672