Parent Holding Company Information (Condensed) - Condensed Statements of Financial Condition (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assets
Cash on hand and in banks	$ 227,108	$ 198,639
Interest bearing cash deposits	406,034	132,322
Cash and cash equivalents	633,142	330,961
Other assets	106,505	81,371
Total assets	18,504,206	13,683,999
Liabilities and Stockholders’ Equity
Subordinated debentures	139,959	139,914
Other liabilities	194,861	164,954
Total liabilities	16,197,165	11,723,266
Common stock	954	923
Paid-in capital	1,495,053	1,378,534
Retained earnings	667,944	541,050
Accumulated other comprehensive income (loss)	143,090	40,226
Total stockholders’ equity	2,307,041	1,960,733	$ 1,515,854	$ 1,199,057
Total liabilities and stockholders’ equity	18,504,206	13,683,999
Parent Company
Assets
Cash on hand and in banks	41,451	23,491
Interest bearing cash deposits	43,975	34,345
Cash and cash equivalents	85,426	57,836
Other assets	11,823	12,966
Investment in subsidiaries	2,369,040	2,063,011
Total assets	2,466,289	2,133,813
Liabilities and Stockholders’ Equity
Dividends payable	14,717	18,821
Subordinated debentures	139,959	139,914
Other liabilities	4,572	14,345
Total liabilities	159,248	173,080
Common stock	954	923
Paid-in capital	1,495,053	1,378,534
Retained earnings	667,944	541,050
Accumulated other comprehensive income (loss)	143,090	40,226
Total stockholders’ equity	2,307,041	1,960,733
Total liabilities and stockholders’ equity	$ 2,466,289	$ 2,133,813