CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Shares of Common Stock (no par value)	Additional Paid in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss)
Balance (in shares) at Dec. 31, 2017			49,328,000
Balance at Dec. 31, 2017	$ 352,207			$ 44,787	$ 299,190		$ 8,230
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	46,595				46,595
Other comprehensive gain (loss), net of tax	50						50
Dividends declared	(13,386)				(13,386)
Dividends reinvested in common stock (in shares)	520			520
Dividends reinvested in common stock			11,000
Stock based compensation (in shares)			206,000
Stock based compensation	5,367			5,367
Stock options exercised (in shares)			113,000
Stock options exercised	787			787
Common stock issued (in shares)			1,000
Common stock issued	26			26
Shares retired for settlement of employee taxes upon issuance of vested equity awards (in shares)			(105,000)
Shares retired for settlement of employee taxes upon issuance of vested equity awards	(4,031)			(4,031)
Common stock issued to acquire a non-controlling interests of nTelos (in shares)			76,000
Balance (in shares) at Dec. 31, 2018			49,630,000
Balance at Dec. 31, 2018	444,232	$ 56,097		47,456	388,496	$ 56,097	8,280
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	55,956				55,956
Other comprehensive gain (loss), net of tax	(7,972)						(7,972)
Dividends declared	(14,442)				(14,442)
Dividends reinvested in common stock (in shares)	499			499
Dividends reinvested in common stock			14,000
Share repurchases (in shares)			(200,000)
Share repurchases	(7,231)			(7,231)
Stock based compensation (in shares)			184,000
Stock based compensation	4,182			4,182
Stock options exercised (in shares)			29,000
Stock options exercised	81			81
Common stock issued	34			34
Shares retired for settlement of employee taxes upon issuance of vested equity awards (in shares)			(62,000)
Shares retired for settlement of employee taxes upon issuance of vested equity awards	$ (2,911)			(2,911)
Common stock issued to acquire a non-controlling interests of nTelos (in shares)			76,000
Balance (in shares) at Dec. 31, 2019	49,671,000		49,671,000
Balance at Dec. 31, 2019	$ 472,428			42,110	430,010		308
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	126,723				126,723
Other comprehensive gain (loss), net of tax	(5,014)						(5,014)
Dividends declared	(16,950)				(16,950)
Dividends reinvested in common stock (in shares)	(2)			(2)
Stock based compensation (in shares)			156,000
Stock based compensation	6,833			6,833
Stock options exercised	36			36
Common stock issued (in shares)			1,000
Common stock issued	31			31
Annual dividend reinvestment (in shares)			12,000
Annual dividend reinvestment	526			526
Shares retired for settlement of employee taxes upon issuance of vested equity awards (in shares)			(48,000)
Shares retired for settlement of employee taxes upon issuance of vested equity awards	$ (2,217)			(2,217)
Common stock issued to acquire a non-controlling interests of nTelos (in shares)			76,000
Balance (in shares) at Dec. 31, 2020	49,868,000		49,868,000
Balance at Dec. 31, 2020	$ 582,394			$ 47,317	$ 539,783		$ (4,706)