CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest and dividend income:
Interest and fees on loans		$ 469,856	$ 293,996	$ 261,383
Interest on deposits in other banks		2,125	539	244
Interest and dividends on securities:
Taxable		36,851	20,305	18,319
Nontaxable		19,956	14,204	13,790
Total interest and dividend income		528,788	329,044	293,736
Interest expense:
Interest on deposits		59,336	26,106	17,731
Interest on short-term borrowings		18,458	6,035	2,894
Interest on long-term borrowings		24,303	17,896	9,145
Total interest expense		102,097	50,037	29,770
Net interest income		426,691	279,007	263,966
Provision for credit losses		13,736	10,802	8,883
Net interest income after provision for credit losses		412,955	268,205	255,083
Noninterest income:
Gains (losses) on securities transactions, net	[1]	383	800	205
Bank owned life insurance income		7,198	6,144	5,513
Loan-related interest rate swap fees		3,554	3,051	4,254
Gain on Shore Premier sale		19,966	0	0
Other operating income		7,145	2,772	3,007
Total noninterest income		104,241	62,429	59,849
Noninterest expenses:
Salaries and benefits		159,378	115,968	110,521
Occupancy expenses		25,368	18,558	18,502
Furniture and equipment expenses		11,991	10,047	9,814
Printing, postage, and supplies		4,650	4,901	4,610
Communications expense		3,898	3,304	3,744
Technology and data processing		18,397	16,132	15,032
Professional services		10,283	7,767	8,051
Marketing and advertising expense		10,043	7,795	7,756
FDIC assessment premiums and other insurance		6,644	4,048	5,406
Other taxes		11,542	8,087	5,448
Loan-related expenses		7,206	4,733	4,168
OREO and credit-related expenses		4,131	3,764	2,600
Amortization of intangible assets		12,839	6,088	7,210
Training and other personnel costs		4,259	3,843	3,359
Merger-related costs		39,728	5,393	0
Other expenses		7,410	5,240	6,869
Total noninterest expenses		337,767	225,668	213,090
Income from continuing operations before income taxes		179,429	104,966	101,842
Income tax expense		30,016	32,790	25,944
Income from continuing operations		149,413	72,176	75,898
Discontinued operations:
Income (loss) from operations of discontinued mortgage segment		(4,280)	1,344	2,412
Income tax expense (benefit)		(1,115)	597	834
Income (loss) on discontinued operations		(3,165)	747	1,578
Net income	[1]	$ 146,248	$ 72,923	$ 77,476
Basic earnings per common share (in dollars per share)		$ 2.22	$ 1.67	$ 1.77
Diluted earnings per common share (in dollars per share)		2.22	1.67	1.77
Dividends declared per common share (in dollars per share)		$ 0.88	$ 0.81	$ 0.77
Basic weighted average number of common shares outstanding (in shares)		65,859,165	43,698,897	43,784,193
Diluted weighted average number of common shares outstanding (in shares)		65,908,573	43,779,744	43,890,271
Service charges on deposit accounts
Noninterest income:
Noninterest income		$ 25,439	$ 18,850	$ 18,168
Other service charges, commissions and fees
Noninterest income:
Noninterest income		5,603	4,593	4,445
Interchange fees, net
Noninterest income:
Noninterest income		18,803	14,974	14,058
Fiduciary and asset management fees
Noninterest income:
Noninterest income		$ 16,150	$ 11,245	$ 10,199

[1] Discontinued operations have an immaterial impact to the Company's Consolidated Statement of Cash Flows. The change in loans held for sale and goodwill impairment losses included in the Operating Activities section above are fully attributable to discontinued operations.