Business Combinations - fair value of the assets purchased, including goodwill, and liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Nov. 03, 2017	Oct. 20, 2017	Apr. 07, 2017
Assets:
Goodwill	$ 148,555	$ 147,578
Bank shares, Inc [Member] | Measurement Period Adjustments [Member]
Assets:
Cash				$ 0
Investment securities				0
Loans, net				0
Fixed assets				0
Core deposit intangibles				0
Goodwill				(99)
Other assets				99
Total assets acquired				0
Liabilities:
Deposits				0
Other liabilities				0
Total liabilities assumed				0
Bank shares, Inc [Member] | Scenario, Previously Reported [Member]
Assets:
Cash				5,485
Investment securities				56,123
Loans, net				136,832
Fixed assets				2,637
Core deposit intangibles				1,275
Goodwill				12,404
Other assets				1,522
Total assets acquired				216,278
Liabilities:
Deposits				182,443
Other liabilities				980
Total liabilities assumed				183,423
Bank shares, Inc [Member] | Restatement Adjustment [Member]
Assets:
Cash				5,485
Investment securities				56,123
Loans, net				136,832
Fixed assets				2,637
Core deposit intangibles				1,275
Goodwill				12,305
Other assets				1,621
Total assets acquired				216,278
Liabilities:
Deposits				182,443
Other liabilities				980
Total liabilities assumed				$ 183,423
Gulf Shore Banc shares Inc [Member]
Assets:
Other assets					$ 358,000
Gulf Shore Banc shares Inc [Member] | Measurement Period Adjustments [Member]
Assets:
Cash					0
Investment securities					0
Loans, net					0
Fixed assets					0
Other real estate owned					0
Core deposit intangibles					0
Goodwill					0
Other assets					0
Total assets acquired					0
Liabilities:
Deposits					0
Other liabilities					0
Total liabilities assumed					0
Gulf Shore Banc shares Inc [Member] | Scenario, Previously Reported [Member]
Assets:
Cash					55,540
Investment securities					316
Loans, net					250,876
Fixed assets					1,307
Other real estate owned					13
Core deposit intangibles					3,927
Goodwill					37,098
Other assets					8,572
Total assets acquired					357,649
Liabilities:
Deposits					285,350
Other liabilities					1,382
Total liabilities assumed					286,732
Gulf Shore Banc shares Inc [Member] | Restatement Adjustment [Member]
Assets:
Cash					55,540
Investment securities					316
Loans, net					250,876
Fixed assets					1,307
Other real estate owned					13
Core deposit intangibles					3,927
Goodwill					37,098
Other assets					8,572
Total assets acquired					357,649
Liabilities:
Deposits					285,350
Other liabilities					1,382
Total liabilities assumed					$ 286,732
Palm Beach Community Bank [Member]
Assets:
Other assets			$ 357,000
Palm Beach Community Bank [Member] | Measurement Period Adjustments [Member]
Assets:
Cash			0
Investment securities			0
Loans, net			(1,772)
Fixed assets			0
Core deposit intangibles			0
Goodwill			1,323
Other assets			449
Total assets acquired			0
Liabilities:
Deposits			0
Other liabilities			0
Total liabilities assumed			0
Palm Beach Community Bank [Member] | Scenario, Previously Reported [Member]
Assets:
Cash			9,301
Investment securities			22,098
Loans, net			272,090
Fixed assets			7,641
Core deposit intangibles			2,523
Goodwill			33,428
Other assets			9,909
Total assets acquired			356,990
Liabilities:
Deposits			268,633
Other liabilities			16,351
Total liabilities assumed			284,984
Palm Beach Community Bank [Member] | Restatement Adjustment [Member]
Assets:
Cash			9,301
Investment securities			22,098
Loans, net			270,318
Fixed assets			7,641
Core deposit intangibles			2,523
Goodwill			34,751
Other assets			10,358
Total assets acquired			356,990
Liabilities:
Deposits			268,633
Other liabilities			16,351
Total liabilities assumed			$ 284,984